WO2021180229A1

WO2021180229A1 - Method for restoring biosensor and device using said method

Info

Publication number: WO2021180229A1
Application number: PCT/CN2021/080609
Authority: WO
Inventors: 黄椿木; 陈界行
Original assignee: 华广生技股份有限公司; 华广美国公司
Priority date: 2020-03-12
Filing date: 2021-03-12
Publication date: 2021-09-16
Also published as: TW202134645A; TWI770871B

Abstract

A method for restoring a biosensor (100) to a proper working state. The biosensor (100) comprises a first electrode (120) and a counter electrode (130), the counter electrode (130) comprises a silver halide material and a silver material, the silver halide material has an inventory level, and in a measurement operation, the inventory level of the silver halide material is consumed. The method comprises the following steps: after the measurement operation, calculating a change in the inventory level; and starting a first refilling operation to refill the fluctuation value of the inventory level, wherein the inventory level is controlled to basically fluctuate between a first threshold (Th1) and a second threshold (Th2).

Description

Method for recovering biosensor and device using this method

Technical field

The present invention relates to a biosensor and a method for determining the size of its counter electrode, in particular to a biosensor for measuring the physiological signal represented by the physiological parameter associated with the object to be measured, and for prolonging the service life of the biosensor method.

Background technique

The population of diabetic patients is growing rapidly, and there is an increasing emphasis on the need to monitor changes in glucose (Glucose) in the body. Therefore, many studies have begun to develop a system that can be implanted in the body for continuous glucose monitoring (CGM) to solve the problem of patients for one day. The inconvenience in life caused by repeated blood sampling and testing.

In the field of an enzyme-based biosensor CGM system, the biochemical reaction signal that depends on the concentration of the analyte is converted into a measurable physical signal, such as an optical or electrochemical signal. For glucose measurement, an electrochemical reaction such as glucose oxidase (GOx) catalyzes the reaction of glucose to produce Gluconolactone and reduced enzymes. The subsequent reduced enzymes will interact with the oxygen in the biological fluids in the body. The transfer then generates the product hydrogen peroxide (H ₂ O ₂ ), and finally the glucose concentration is quantified by the oxidation reaction of the _{catalyzed product H 2} O _{2. The reaction formula is as follows.}

Glucose+GOx(FAD)→GOx(FADH ₂ )+Gluconolactone

GOx(FADH ₂ )+O ₂ →GOx(FAD)+H ₂ O ₂

In the above reaction, FAD (Flavin Adenine Dinucleotide) is the active center of GOx.

Users usually wear CGM for a long period of time, for example, 14 days or more, so miniaturization becomes an inevitable trend. The basic structure of CGM includes: (a) Biosensor, used to measure physiological signals corresponding to human glucose concentration; and (b) Transmitter, used to transmit these physiological signals. The biosensor can be a two-electrode system or a three-electrode system. In the three-electrode system biosensor, it includes a working electrode (WE), a counter electrode (CE) and a reference electrode (RE). The biosensor of the two-electrode system includes a working electrode (WE) and a counter electrode (CE). The counter electrode also functions as a reference electrode, so it is sometimes called a counter/reference electrode (R/C). The suitable material for the reference electrode in the three-electrode system biosensor and the counter electrode as the reference electrode in the two-electrode system biosensor for stable measurement of glucose concentration is silver/silver chloride (Ag/AgCl). However, after the sensor is implanted in the organism, when the working electrode undergoes oxidation-reduction reaction to measure the glucose concentration, the corresponding reference electrode (RE) or reference/counter electrode (R/C) undergoes a reduction reaction to make the silver chloride The reduction to silver causes the silver chloride to be consumed. In addition, if the sensor implanted in the organism is a sensor with a two- or three-electrode system, the silver chloride on the reference electrode will be lost due to the dissociation of silver chloride in the body fluid, which will cause the problem of drifting to the reference voltage. However, due to the reaction of the reference/counter electrode (R/C) of the two-electrode system, the consumption of silver chloride is even higher than that of the three-electrode system. Therefore, the service life of the sensor is limited by the silver chloride content on the counter electrode and/or reference electrode.

There are also many inventions that have been proposed to address the issue of the service life of biosensors. Taking a two-electrode system as an example, the consumption of the counter electrode is about 1.73 millicoulombs (mC) per day at an average sensing current of 20 nanoamperes (nA). Assuming the length, width and height of the counter electrode are 3.3 mm, 0.25 mm, and When the electrode capacity (Capacity) of the original design is only 6mC at 0.01 mm, the stable measurement state can be maintained for about one day at most. However, if you want to extend the service life, if you want to implant the biosensor under the skin for 16 consecutive days of glucose monitoring, the capacity of the electrode must be at least 27.68mC. The current technology does not change the width and thickness. The length of the counter electrode may need to be as long as 15.2 mm. Therefore, the prior art attempts to extend the length of the counter electrode to more than 10 mm, and in order to avoid implanting deep into the subcutaneous tissue, these biosensors need to be implanted at an oblique angle. Therefore, it causes problems such as a larger implantation wound and a higher risk of infection to the patient, and due to the long implantation length, the pain during implantation is also more pronounced.

US 8,620,398 describes a biosensor, which is mainly a three-electrode system. Although the reference electrode basically does not participate in the chemical reaction, the silver chloride is still gradually consumed in the internal environment, but the consumption rate is slower than that of the two-electrode system, which is disclosed in the article. When AgCl is depleted, regeneration is performed. The step of determining depletion includes determining that the output current of the transmitter is noisy. Will be activated to restore AgCl to the amount required for enough measurements. Then until the next time the noise occurs again, AgCl needs to be recharged again. It can be understood that although US 8,620,398 considers that AgCl will be consumed in the measurement and AgCl recharge is performed when the biosensor fails. However, the measured value at the time of failure is no longer credible. It is necessary to wait for the biosensor to complete the AgCl refilling procedure to obtain the correct measured value, temporarily adopt the blood sampling method, or skip this measurement directly. This problem is for the patient or People who need to know the blood glucose concentration at the time are always troubled. In addition, since this type of biosensor has to cope with at least several consecutive or even multiple measurements over several days, a large amount of AgCl must be prepared, but it will inevitably cause the problem of a longer implantation length of the biosensor. It has not been proposed that real-time AgCl refilling can be used to provide uninterrupted measurement, a biosensor with a shorter implant length and a longer service life.

US9,351,677 is mainly a two-electrode system. The reference/counter electrode (R/C) participates in the chemical reaction, so silver chloride is consumed by the electrochemical reaction. The article proposes an analyte sensor with increased AgCl capacity, which uses H ₂ O ₂ regenerates the AgCl on the reference electrode, but because H ₂ O _{2 is} easily reduced to H ₂ O or oxidized to O ₂ , it is not easy to exist stably in the human body. Therefore, during regeneration/recharging, _{the concentration of H 2} O ₂ in the body may not be sufficient to stably recharge enough AgCl, and the biosensor needs to be equipped with a larger AgCl electrode size, and its implanted end is also long. Up to 12mm.

The service life of the biosensor depends on the amount of silver halide present in the counter electrode. However, the size of the counter electrode also depends on the amount of silver halide. The longer the life of the biosensor, the greater the amount of silver halide. The larger the amount of silver halide, the larger the size of the counter electrode. The larger the size of the counter electrode, the longer the implantation length into the patient. The longer the implant length for the patient, the greater the discomfort suffered by the patient. The present disclosure provides a solution to reduce the size of the counter electrode, provides a method for quantifying the initial amount of silver halide required on the counter electrode, and provides a method for intelligently starting the refill halogenation when needed. The silver method and device do not need to wait for the silver halide depletion signal to appear (for example, physiological signal noise) before performing silver halide recharging. Instead, an appropriate range can be selected as the threshold interval to control the inventory level of silver halide to be maintained here. Within the threshold interval. Therefore, the present invention provides a biosensor capable of providing uninterrupted measurement, stable refilling of AgCl, prolonging its service life, and miniaturizing the effect of the small size of the implanted end, which can further reduce the cost of the product. Manufacturing costs, and these effects can solve the aforementioned problems that are difficult to overcome by the known technology.

In view of the shortcomings of the known technology, the applicant in this case, after careful experimentation and research, and with a spirit of perseverance, finally conceived the case, which can overcome the shortcomings of the previous technology. The following is a brief description of the case.

Summary of the invention

Through the recharging technology of the present invention, the size of the counter electrode signal sensing section in the micro biosensor of the present invention can be reduced, thereby reducing biological toxicity and enabling the micro biosensor to have a prolonged service life. In addition, the reduced size of the electrode can shorten the length of the implanted end of the sensor, thus reducing the pain of implantation for the user. In particular, the refilling technology of the present invention is used to control the timing and amount of refilling of silver chloride. Therefore, even when the user's glucose concentration fluctuates greatly, the micro sensor of the present invention can still recharge in real time and automatically. Charge the consumed silver chloride to maintain the inventory of silver chloride within a predetermined interval. Therefore, the obtained physiological signals and physiological parameters maintain a stable proportional relationship. Through the recharging method of the present invention, the recharging rate of silver chloride does not have to be completely positively correlated with the decrease rate of silver chloride during the measurement, and it also includes the recharging of silver chloride immediately after each measurement. Charging method.

One of the objectives of this case is to provide a method for controlling the recharge of silver halide material in a biosensor that is implanted under the skin to measure the physiological parameters associated with the analyte in the biological fluid. Signal, the biosensor at least includes a first electrode and a counter electrode, the counter electrode includes a silver halide material and a silver material, the silver halide material has an inventory level in the silver halide material and the silver material, so The refill control method includes the following steps: after a measurement operation, a measurement value of the physiological signal is obtained, wherein the inventory level decreases after the measurement operation; If the condition is met, calculate the variation value of the inventory level during the predetermined number of times, and start the first refill operation to refill the variation value of the inventory level, and the predetermined number of times is a positive integer , Wherein the inventory level substantially changes between the first threshold and the second threshold.

One of the objectives of this case is to provide a physiological signal measuring device that can control the inventory level of the silver halide material of the biosensor. The silver halide material has an initial inventory, and the inventory level represents the current The inventory is used to make the physiological signal measurement device perform a refill operation to restore the silver halide material to the inventory level, the physiological signal measurement device includes: the biosensor, includes: a first electrode, and The first pair of electrodes includes the silver halide material and the silver material; and a transmission unit, which is coupled to the biosensor, and includes a processor, configured to reduce the consumption of the inventory when the measurement operation is started. , When the refill operation is started, the inventory is increased by the refill, and the inventory level is calculated, wherein the processor controls the inventory level to basically change between a first threshold and a second threshold .

One of the objectives of this case is to provide a method for restoring a biosensor to a proper working state. The biosensor includes a first electrode and a counter electrode. The counter electrode includes a silver halide material and a silver material. The silver halide material has a stock. In the measuring operation, the inventory level of the silver halide material is consumed. The method includes the following steps: after the measuring operation, calculating the change in the inventory level; and activating the first A refill operation is performed to refill the variation value of the inventory level, wherein the inventory level is controlled to vary substantially between a first threshold and a second threshold.

Description of the drawings

The above-mentioned objects and advantages of the present invention will become more immediately apparent to those with ordinary knowledge in the technical field after referring to the following detailed description and accompanying drawings.

[Figure 1] is a schematic diagram of a physiological signal measuring device according to an embodiment of the present invention.

[Fig. 2A] is a schematic front view of the micro biosensor of the present invention.

[Fig. 2B] is a schematic diagram of the back of the micro biosensor of the present invention.

[Fig. 2C] is a schematic cross-sectional view along the line A-A' in Fig. 2A of the present invention.

[Fig. 2D] is a schematic cross-sectional view of the second embodiment of the micro biosensor of the present invention.

[Fig. 3A] is a flowchart of a method for recharging silver halide material in a biosensor according to an embodiment of the present invention.

[Fig. 3B] is a flowchart of a method for recharging silver halide material in a biosensor according to another embodiment of the present invention.

[Fig. 3C] is a flowchart of a method for recharging silver halide material in a biosensor according to another embodiment of the present invention.

[Fig. 3D] is a flowchart of a method for recharging silver halide material in a biosensor according to another embodiment of the present invention.

[Fig. 3E] is a flowchart of a method for recharging silver halide material in a biosensor according to another embodiment of the present invention.

[FIG. 4A] to [FIG. 4H] are schematic diagrams of the inventory level of various embodiments of the present invention.

[Fig. 5A] is the constant voltage circuit in the measurement mode in the present invention.

[Fig. 5B] is the constant voltage circuit in the recharging mode in the present invention.

[Fig. 6A] is a schematic diagram of the variation curve of the inventory level according to an embodiment of the present invention.

[Fig. 6B] is a schematic diagram of the variation curve of the inventory level according to another embodiment of the present invention.

[Fig. 6C] is a schematic diagram of the variation curve of the inventory level according to another embodiment of the present invention.

[Fig. 6D] is a schematic diagram of the variation curve of the inventory level according to another embodiment of the present invention.

[Fig. 6E] is a schematic diagram of the variation curve of the inventory level according to another embodiment of the present invention.

[FIG. 7A] is a current schematic diagram of the constant voltage circuit of the present invention in the first mode alternately performing the measurement mode and the recharge mode.

[Fig. 7B] is a schematic diagram of the current of the constant voltage circuit of the present invention in the second mode alternately performing the measurement mode and the recharge mode.

[Fig. 7C] is a current schematic diagram of the constant voltage circuit of the present invention in the third mode alternately performing the measurement mode and the recharge mode.

[FIG. 7D] is a current schematic diagram of the constant voltage circuit of the present invention in the fourth mode alternately performing the measurement mode and the recharge mode.

[Fig. 7E] is a current schematic diagram of the constant voltage circuit of the present invention in the fifth mode alternately performing the measurement mode and the recharge mode.

[FIG. 7F] is a current schematic diagram of the constant voltage circuit of the present invention in the sixth mode alternately performing the measurement mode and the recharge mode.

[Fig. 8A] The constant current circuit with step-switching in the measurement mode of the present invention.

[Fig. 8B] The constant current circuit with step-switching in the recharge mode of the present invention.

[Fig. 9A] The constant current circuit with stepless switching in the measurement mode of the present invention.

[Fig. 9B] The constant current circuit with stepless switching in the recharge mode in the present invention.

[FIG. 10A] is a voltage schematic diagram of the constant current circuit of the present invention in the first mode alternately performing the measurement mode and the recharge mode.

[FIG. 10B] is a voltage schematic diagram of the constant current circuit of the present invention in the second mode alternately performing the measurement mode and the recharge mode.

[FIG. 10C] is a voltage schematic diagram of the constant current circuit of the present invention in the third mode alternately performing the measurement mode and the recharge mode.

[Fig. 10D] is a schematic diagram of the constant current circuit of the present invention alternately performing the measurement mode and the recharge mode in the third mode.

[Figure 11] is a method for determining an analyte according to an embodiment of the present invention.

[Fig. 12] is a method for determining an analyte according to another embodiment of the present invention.

[Fig. 13A] is a schematic front view of the first embodiment of the micro biosensor of the present invention.

[Fig. 13B] is a schematic back view of the first embodiment of the micro biosensor of the present invention.

[Figure 13C] is a schematic cross-sectional view taken along the line A-A' in Figure 2A of the present invention.

[Fig. 14A] is a schematic cross-sectional view of the second embodiment of the micro biosensor of the present invention.

[Fig. 14B] is a schematic cross-sectional view of the third embodiment of the micro biosensor of the present invention.

[Fig. 14C] is a schematic cross-sectional view of the fourth embodiment of the micro biosensor of the present invention.

[Fig. 14D] is a schematic cross-sectional view of the fifth embodiment of the micro biosensor of the present invention.

[Fig. 14E] is a schematic cross-sectional view of the sixth embodiment of the micro biosensor of the present invention.

[Fig. 14F] is a schematic cross-sectional view of the seventh embodiment of the micro biosensor of the present invention.

[Fig. 14G] is a schematic cross-sectional view of the eighth embodiment of the micro biosensor of the present invention.

[Fig. 15A] is the constant voltage circuit in the measurement mode in the present invention.

[Fig. 15B] is the constant voltage circuit in the recharging mode in the present invention.

[Fig. 16A] The constant current circuit with step-switching in the measurement mode of the present invention.

[Fig. 16B] The constant current circuit with step-switching in the recharge mode in the present invention.

[FIG. 17A] The constant current circuit with stepless switching in the measurement mode of the present invention.

[Fig. 17B] The constant current circuit with stepless switching in the recharge mode in the present invention.

[Fig. 18A] is a schematic front view of the first embodiment of the micro biosensor of the present invention.

[Fig. 18B] is a schematic back view of the first embodiment of the micro biosensor of the present invention.

[Fig. 18C] is a schematic cross-sectional view taken along the line A-A' in Fig. 2A of the present invention.

[Fig. 19A] is a schematic cross-sectional view of the second embodiment of the micro biosensor of the present invention.

[Fig. 19B] is a schematic cross-sectional view of the third embodiment of the micro biosensor of the present invention.

[Fig. 19C] is a schematic cross-sectional view of the fourth embodiment of the micro biosensor of the present invention.

[Fig. 20A] It is a constant voltage circuit that can execute the measurement mode and the recharge mode according to the first method of the present invention.

[Fig. 20B] is a constant voltage circuit that can perform measurement mode and recharge mode according to the second method of the present invention.

[Fig. 20C] is a constant voltage circuit that can perform measurement mode and recharge mode according to the third method of the present invention.

[Fig. 21] It is a constant current circuit that can perform stepwise switching between the measurement mode and the recharge mode in the present invention.

[Fig. 22] is a constant current circuit that can perform stepless switching between the measurement mode and the recharge mode in the present invention.

[FIG. 23A] is a schematic diagram of the constant current or constant voltage circuit of the present invention in a measurement mode and a recharge mode according to an embodiment.

[Fig. 23B] is a schematic diagram of the constant current or constant voltage circuit of the present invention in the measurement mode and the recharge mode according to another embodiment.

[Fig. 24] is a flowchart according to an embodiment of the present invention.

Detailed ways

The invention proposed in this case will be fully understood by the following examples, so that those with ordinary knowledge in the technical field can complete it. However, the implementation of this case is not limited by the following examples. The technical field Those with ordinary knowledge can still deduce other embodiments based on the spirit of the disclosed embodiments, and these embodiments should fall within the scope of the present invention.

Unless otherwise restricted in a specific example, the following definitions apply to the terms used throughout the specification.

The term "amount" or "inventory amount" refers to the capacity of silver halide (AgX) or silver chloride (AgCl) in the counter electrode, and is preferably measured in microcoulomb (μC), millicoulomb (mC) or coulomb (C ) Is expressed in units of, but not limited to, expressed in terms of weight percentage concentration wt%, number of moles, molar concentration, etc.

The curves or straight lines schematically shown in the drawings do not necessarily represent their true shapes. For example, a straight line or a curve may have fluctuations along the normal direction of the line, or may have various possible turns; or The distance, length or height shown in does not represent an absolute measure, unless explicitly stated.

Please refer to FIG. 1, which is a schematic diagram of the physiological signal measuring device of the present invention. The physiological signal measuring device 10 of the present invention can be used to be implanted under the skin to measure the physiological signal of the physiological parameter associated with the analyte in the biological fluid. The physiological signal measurement device 10 of the present invention includes a micro biosensor 100 and a transmission unit 200, wherein the transmission unit 200 is electrically connected to the micro biosensor 100, and has a processor 210, a power supply 220, a voltage application unit 230, a temperature sensing unit 240 and Communication unit 250. The power supply 220 controls the voltage applying unit 230 through the processor 210 to provide voltage to the micro biosensor 100 for measuring the physiological signal, and the temperature sensing unit 240 measures the temperature of the biological body, so the temperature measurement signal and the physiological signal measured by the micro biosensor 100 The signal is transmitted to the processor 210, and the processor 210 calculates the physiological signal into a physiological parameter. The communication unit 250 may perform wired or wireless transmission with the user device 20.

Please continue to refer to FIG. 1, the transmission unit 200 may optionally include a timer 260 coupled to the processor 210, for example, within 5 seconds, within 15 seconds, within 30 seconds, within one minute, and ten minutes. Timekeeping at a fixed time interval such as within one hour, within two hours, within four hours, within one day, within one week, or within one month. The timer 260 can also be set to send a signal to the processor 210 at one or more settable time points.

Please refer to FIGS. 2A and 2B, which are schematic diagrams of the front and back of the micro biosensor of the present invention. The micro biosensor 100 of the present invention includes a substrate 110, a working electrode 120 and a counter electrode 130 disposed on the substrate 110, and a chemical reagent 140 surrounding the working electrode 120 and the counter electrode 130 (as shown in FIG. 2C). The material of the substrate 110 can be any material that is known to be suitable for use in electrode substrates and preferably has flexibility and insulation properties, such as but not limited to polymer materials such as polyester and polyimide. The aforementioned polymer materials can be used singly or in combination of multiple types. The substrate 110 has a surface 111 (that is, the first surface), an opposite surface 112 (that is, the second surface) opposite to the surface 111, a first end 113 and a second end 114, and the substrate 110 is divided into 3 regions, which are respectively close to The signal output area 115 of the first end 113, the sensing area 116 close to the second end 114, and the connection area 117 between the signal output area 115 and the sensing area 116. The working electrode 120 is disposed on the surface 111 of the substrate 110 and extends from the first end 113 to the second end 114 of the substrate 110. The working electrode 120 includes a signal output section 121 located in the signal output area 115 of the substrate 110 and a signal sensing section 122 located in the sensing area 116 of the substrate 110. The material of the working electrode 120 includes, but is not limited to: carbon, platinum, aluminum, gallium, gold, indium, iridium, iron, lead, magnesium, nickel, manganese, molybdenum, osmium, palladium, rhodium, silver, tin, titanium, zinc, Silicon, zirconium, a mixture of the foregoing elements, or derivatives of the foregoing elements (such as alloys, oxides or metal compounds, etc.). Preferably, the material of the working electrode 120 is a noble metal, a derivative of noble metal, or a combination of the foregoing, more preferably Ground, the working electrode 120 is a platinum-containing material.

The counter electrode 130 is disposed on the opposite surface 112 of the substrate 110 and extends from the first end 113 to the second end 114 of the substrate 110. The counter electrode 130 includes a signal output section 131 located in the signal output area 115 of the substrate 110 and a signal sensing section 132 located in the sensing area 116 of the substrate 110. The material on the surface of the counter electrode 130 includes silver and silver halide, and the silver halide is preferably silver chloride or silver iodine, so that the counter electrode 130 also functions as a reference electrode That is, the counter electrode 130 of the present invention can (1) form an electronic circuit with the working electrode 120, so that the working electrode 120 is smoothly connected to ensure that the electrochemical reaction occurs on the working electrode 120; and (2) provide a stable relative potential as Reference potential. Therefore, the working electrode 120 and the counter electrode 130 of the present invention form a two-electrode system. In order to further reduce the cost and improve the biocompatibility of the biosensor of the present invention, the silver/silver halide can be mixed with carbon. For example, the silver/silver halide is mixed with carbon glue, and the silver halide content only needs to make the counter electrode 130 stable. Just execute the set measurement action. The surface of the counter electrode 130 can also be covered with a conductive material to prevent silver halide from dissolution, thereby protecting the counter electrode 130. The conductive material is mainly a conductive material that does not affect the measurement performance of the working electrode, such as conductive material. It is Carbon.

In another embodiment, the biosensor is not limited to a wire-type or stacked-type electrode structure.

In another embodiment of the present invention, the initial amount of silver halide may be zero before the biosensor is ready to be shipped out of the factory for sale. In this case, there is no silver halide on the counter electrode 130 of the biosensor. After the biosensor is subcutaneously implanted in the patient and during the initial recharge period before the first measurement, the silver coated on the counter electrode 130 through oxidation can be recharged with the initial amount of silver halide on the counter electrode 130 .

The chemical reagent 140 covers at least the signal sensing section 122 of the working electrode 120 and the surface of the counter electrode 130 located in the sensing area 116. In another embodiment, the chemical reagent 140 covers at least the signal sensing section 122 of the working electrode 120 (not shown). In other words, the counter electrode 130 may not be covered by the chemical reagent 140. The sensing area 116 of the micro biosensor 100 can be implanted subcutaneously so that the signal sensing section 122 of the working electrode 120 measures the physiological signal associated with the analyte in the biological fluid, and the physiological signal will be transmitted to the signal output of the working electrode 120 In section 121, the signal output section 121 is sent to the processor 210 to obtain physiological parameters. In addition to obtaining the physiological parameters from the transmission unit 200, the physiological parameters may also be transmitted to the user device 20 via wireless/wired communication, such as a smart phone, a physiological signal receiver, or a blood glucose meter.

Please refer to FIG. 2C, which is a schematic cross-sectional view along the line AA' in FIG. In FIG. 2C, the working electrode 120 is disposed on the surface 111 of the substrate 110, the counter electrode 130 is disposed on the opposite side surface 112 of the substrate 110, and the surfaces of the working electrode 120 and the counter electrode 130 are covered with a chemical reagent 140. Basically, the chemical reagent 140 covers at least a part of the surface of the working electrode 120. The micro biosensor 100 of the present invention performs the measurement step during the measurement period, and performs the recharge step during the recharge (ie regeneration) period. When the measurement step is performed, the voltage of the working electrode 120 is higher than the voltage of the counter electrode 130, so that the current flows from the working electrode 120 to the direction of the counter electrode 130, so that the working electrode 120 undergoes an oxidation reaction (that is, the working electrode 120, the chemical reagent 140) The electrochemical reaction between the analyte and the analyte) is used to measure the physiological signal, and a reduction reaction occurs on the counter electrode 130, so that the silver halide in the counter electrode 130 is consumed and dissociated into silver (Ag) and halide ions (X ⁻ ). Since the silver halide in the counter electrode 130 is consumed, the silver halide in the counter electrode 130 needs to be recharged to perform the next measurement step. When the recharging step is performed, the voltage of the counter electrode 130 is higher than the voltage of the working electrode 120, so that the current flows from the counter electrode 130 to the direction of the working electrode 120, and the counter electrode 130 is oxidized to cause the silver to react with the halide ions in the living body. Or AgCl oxidized (or dissociated) Cl ^- combined to recharge the silver halide. The detailed measurement steps and recharge steps are shown in Figure 11.

In another embodiment, the working electrode 120 and the counter electrode 130 of the present invention may be disposed on the same surface of the substrate 110, that is, both the working electrode 120 and the counter electrode 130 are disposed on the surface 111 or the opposite surface 112 of the substrate 110, such as Shown in Figure 2D. Similarly, when the measurement step is performed, current flows from the working electrode 120 to the counter electrode 130, and the working electrode 120 is oxidized to measure physiological signals. The silver halide in the counter electrode 130 is consumed and dissociated into silver ( Ag) and halogen ions (X ^-). When the recharging step is performed, current flows from the counter electrode 130 to the working electrode 120, so that the counter electrode 130 undergoes an oxidation reaction to combine silver and halide ions to recharge the silver halide.

2C-2D above, the detailed electrode stack is omitted, and only the electrode positions are shown.

In any of the above embodiments, in order to prevent the silver electrode material from being broken due to excessive chlorination, a layer of conductive material (such as carbon) may be added between the opposite side surface 112 of the substrate 110 and the silver of the opposite electrode 130. However, if the bottom layer of the counter electrode 130 is carbon, the resistance at the switch will be too high. Therefore, a conductive layer, such as silver, can be added between the carbon conductive material and the opposite surface 112 of the substrate 110 to reduce the signal. The impedance of the output end makes the counter electrode 130 of the present invention form a conductive layer, a carbon layer, and a silver/silver halide layer in sequence starting from the opposite surface 112 of the substrate 110.

In other embodiments, the silver halide of the counter electrode material is not excluded as silver chloride or silver sulfide, or other electrode materials based on silver redox reaction, such as silver acetate, phosphoric acid. Silver (silver phosphate). In other embodiments, the method for restoring the inventory level of electrode materials of the present invention is not limited to the above-mentioned materials. For example, all other electrodes with similar features can be applied to the method of restoring the biosensor and the device using this method.

Please refer to Figures 1, 2C or 2D, and 5A-5B. The present invention proposes a physiological signal measuring device 10 that can control the inventory level of silver halide materials of the micro biosensor 100. The silver halide material has an initial inventory I ₀ , The inventory level represents the inventory of silver halide materials at the time and is used to make the physiological signal measurement device perform a refill operation to restore the inventory level of the silver halide material. The physiological signal measurement device 10 includes: a biosensor 100, including: a first electrode and The counter electrode 130, in a two-electrode system, the first electrode is the working electrode 120, and the counter electrode 130 includes a silver halide material and a silver material; and a transmission unit 200, coupled to the micro biosensor 100, and includes: a processor 210 , Is configured to reduce the consumption of inventory when the measurement operation is started, and increase the inventory when the refill operation is started, and calculate the inventory level. The processor controls the inventory level to basically vary between the first threshold and the second threshold. In other embodiments, it can also be implemented in the electrode system as shown in FIG. 13C or FIG. 14A-F.

3A-3E are flowcharts of methods for recharging silver halide materials in biosensors according to different embodiments of the present invention. 3A is a flowchart of a method for recharging silver halide material in a biosensor according to an embodiment of the present invention. Please refer to Figure 3A, the silver halide material has an inventory level, and the inventory level changes with the measurement and refilling operations: in the measurement operation, the inventory level will decrease; and in the refilling operation, the inventory level will increase . The recharging method of the present invention includes step S11: the processor 210 receives the measurement instruction; step S12: the power supply 220 controls the voltage applying unit 230 through the processor 210 to provide voltage to the biosensor 100 to measure the physiological signal and obtain the measured value; Step S13: The processor determines the operating conditions for recharging according to the measured value. For example, it determines the application time and the magnitude of the recharging voltage according to the accumulated consumption to start the recharging, and stops the recharging when the time is reached. Step S14: Perform refilling according to the operating conditions of refilling; Step S15: Calculate the current inventory level during the refilling operation; Step S16: The processor performs the refill according to different preset thresholds (Th1, Th2, Th3, Th4, predetermined value S, etc.), determine whether the inventory level is between the first threshold and the second threshold: if not, continue the current refill operation, or go to step S11 to wait for the next measurement instruction to proceed to the next measurement and Refill cycle; if so, stop refilling and go to step S11 to receive the measurement instruction again, or go directly to step S12 for the next measurement and refill cycle.

The refill time and refill amount of the inventory level when the processor performs the refill operation can be calculated based on a consumption of each measurement operation performed, such as total consumption, partial consumption or average consumption, and a period of execution. One or a combination of the cumulative amount of consumption of each measurement operation in the measurement operation, the natural consumption of the electrode, or a combination thereof is dynamically adjusted. The calculation of the refill inventory can also be matched with the user’s glucose concentration index factor. The higher the glucose concentration, the more the consumption of silver halide materials, so that the reduction rate of silver halide materials during the measurement operation does not have to be the same as that of silver halide materials. The generation rate is positively correlated, and the timing and amount of regeneration of the silver halide material can be controlled by the charging method.

In the present invention, the inventory level is based on the percentage of the silver halide material in the counter electrode in the silver halide material and the silver material, or the cumulative value of the consumption of the silver halide material in each measurement operation and each recharge operation. The difference between the cumulative value of the silver halide material refilling amount is used as the calculation method. In other embodiments, the inventory level can also be a unit amount of the silver halide material in the counter electrode between the silver halide material and the silver material, for example, in coulombs. The number is presented, but is not limited to the weight percentage concentration wt%, the number of moles, and the concentration of moles. Regarding the inventory level, other mathematical methods or electrical units can also be used to calculate the inventory level.

3B is a flowchart of a method for recharging silver halide materials in a biosensor according to another embodiment of the present invention, using the difference as the inventory level as the judgment parameter to be applied to the physiological signal measuring device to perform the recharging operation . Of course, if the difference here is replaced with the inventory level, it can also be applied in Figure 3B.

Please refer to Figure 3B. The silver halide material has an inventory. When the biosensor leaves the factory, the inventory at this time is the initial inventory, and the inventory decreases or increases with the operation of measurement and refilling. The recharging method according to an embodiment of the present invention includes step S21: the processor 210 receives the measurement instruction; step S22: the power supply 220 controls the voltage applying unit 230 through the processor 210 to provide voltage to the biosensor 100 for physiological signal measurement , Obtain the measured value, and convert the current consumption of the silver halide material; Step S23: The processor calculates the silver halide inventory level (the proportion of silver halide, or the cumulative value of each consumption and the accumulation of each recharge Step S24: Determine whether the current proportion (or difference) satisfies the recharge condition: if not, wait for the next measurement instruction; if yes, then Step S25: start the recharge operation; measure and measure Measurement step S26: Determine whether the proportion (or difference) meets the conditions for stopping recharging, if not, continue the current recharging operation, or go to step S21 to wait for a new measurement instruction; if yes, stop recharging and wait for the next one For the measurement instruction, proceed to step S21 to receive the measurement instruction again, or proceed directly to step S22 to perform the next measurement and refill cycle. The recharging operation shown in FIG. 3B stops when the recharging amount approximately equal to the variable value is reached. In order to facilitate the distinction, this recharging operation may be referred to as the first recharging operation.

In the method for restoring the biosensor of the present invention as described above, other judgment parameters can also be added. For example, under certain conditions, the recharge operation can be additionally started, please refer to Figure 3C. FIG. 3C is a flowchart of a method for recharging silver halide materials in a biosensor according to another embodiment of the present invention. Step S31: After receiving the measurement instruction, step S32 not only obtains the measurement value, but also calculates the cumulative value of the number of measurements N. For example, after the first measurement, such as computer language calculation, at this time N=N+1, that is N increases from 0 to 1. Step S33: Calculate the proportion of the inventory (or a difference between the cumulative value of each consumption and the cumulative value of each refill). Step S34: Determine whether one of the inventory level, the difference value, and the cumulative value of the measurement times meets the refilling condition, if not, wait for the next measurement instruction; if yes, then step S35: start the refill operation; step S36: Calculate the gradually increasing inventory level in the refilling operation; step S37: determine whether the inventory level meets the refilling stop condition: if not, continue the current refilling operation; if so, stop the refilling and wait for the next measurement instruction. Step S38: The cumulative value of the number of measurements is reset to zero. After the measurement instruction is received again, step S31 is entered again.

In addition to the method for restoring the biosensor of the present invention as described above, other judgment parameters can also be used independently or in combination. For example, according to another embodiment of the present invention, if this recovery method is implemented separately, the fluctuation of the inventory level can be controlled within a small (ie more stable) range until the inventory level reaches a certain lower limit. Only increase the recharging position difference, recharging current or recharging time to increase the larger single recharging capacity. 3D is a flowchart of a method for recharging silver halide material in a biosensor according to another embodiment of the present invention. Please refer to FIG. 3D, steps S44 to S47 are similar to steps S34 to S37 of FIG. 3C. Step S42: Measure to obtain the measured value, and calculate the number of measurements (N=N+1). Under the condition that the number of measurement operations N reaches the predetermined number of times P (that is, when N=P and P is a predetermined positive integer), calculate The cumulative measurement value during the period from N=0 to N=P, or the variation value of the inventory level (for example, the difference (or absolute value) of the inventory when N=0 to N=P), that is, N=0 to N = the cumulative consumption between P, and then step S43: start the first recharge operation to recharge the recharge approximately equal to the variable value. After the recharging is stopped, step S48: the number of measurements N is reset to zero. After the measurement instruction is received again, step S41 is entered again.

This method can be controlled after each measurement (of course, it can also be after each measurement, such as after a single measurement operation that consumes too much, or the cumulative consumption of multiple measurement operations. Large time) start a recharge operation.

If this method of recharging is implemented in combination with the method of Figures 3A, 3B, or 3C, for example, it can be expected that the parameter setting value of the biosensor may be exceeded due to excessive changes in the measured physiological parameters. Therefore, it is possible to prevent the problem that the biosensor will fail sooner or later as the inventory level continues to increase or decrease.

3E is a flowchart of a method for recharging silver halide materials in a biosensor according to another embodiment of the present invention. Please refer to Figure 3E, step S51: receiving measurement instructions; step S52: measuring and obtaining the measured value; step S53: calculating the current consumption and cumulative consumption (if it is the first measurement, the cumulative consumption is the current Consumption); Step S54: Determine whether the accumulated consumption satisfies the recharge condition: if not, wait for the next measurement instruction; if it is, then Step S55: Determine the operating condition for recharge. For example, the size and/or time of the applied recharge voltage is determined according to the amount of accumulated consumption, or different threshold values (Th1, Th2, Th3, Th4, predetermined value S, etc.) are given. Step S56: Start the refilling operation; Step S57: Calculate the gradually increasing inventory level during the refilling operation; Step S58: Determine whether the inventory level meets the conditions for stopping the refilling: If not, continue the current refilling operation; if so, then Stop refilling and wait for the next measurement instruction. After the measurement instruction is received again, step S51 is entered again.

4A-4H are schematic diagrams of the variation curve of the inventory level of various embodiments of the present invention, in which FIGS. 4A-4D and 4H are schematic diagrams of the variation of the inventory level that may occur when only the method of FIG. 3B, 3C or 3D is used . Please refer to Fig. 4A. The inventory quantity _{starts from the initial inventory quantity I 0.} After several measurement operations, when the inventory level gradually drops to less than or equal to the first threshold Th1, the refill operation is initiated until the inventory level reaches the second threshold. Stop recharging operation at Th2. In addition, a predetermined value S can be set between the first threshold Th1 and the second threshold Th2 as another threshold. When the inventory level reaches S, the refill operation is stopped. Fig. 4A shows the situation when Th2=S.

Please refer to FIG. 4B. At this time, the predetermined value S is set equal to the initial inventory I ₀ to replace the second threshold Th2. Therefore, after the refill operation is started, the refill operation is stopped when the _{inventory level reaches the initial inventory level I 0.}

Please refer to FIG. 4C. At this time, the predetermined value S is set to be greater than the initial inventory I ₀ and less than the second threshold Th2. Therefore, after the refill operation is initiated, the inventory level rises to _{a predetermined value S greater than the initial inventory I 0} and then the refill operation is stopped.

Please refer to FIG. 4D. At this time, the predetermined value S is set to be less than the initial inventory amount and greater than the first threshold Th1. Therefore, after the refill operation is started, the inventory level rises to _{a predetermined value S less than the initial inventory I 0} and then the refill operation is stopped.

4E-4H are schematic diagrams of possible changes in inventory levels when the method of FIG. 3A or 3E is combined with one of the methods of FIGS. 3B to 3D. Please refer to Figure 4E. The inventory level _{starts from the initial inventory level I 0.} After one or more measurement operations have been initiated and the first refill operation of the method shown in Figure 3A or 3E has been initiated, the inventory level gradually drops to When it is less than or equal to the first threshold Th1, the refill operation (referred to as the second refill operation) as shown in FIGS. 3B to 3D is started, and the refill operation is stopped when the inventory level reaches the second threshold Th2 (or S=Th2).

Please refer to FIG. 4F, after one or more determination operations have been initiated and the first refill operation of the method shown in FIG. 3A or 3E has been started once or more times, when the inventory level gradually rises to be greater than or equal to the second threshold Th2, The second recharging operation as shown in FIGS. 3B to 3D will not be started, and the second recharging operation will not be started until the inventory level is less than or equal to the first threshold Th1.

Please refer to Figures 4G and 4H. The difference between the two figures lies in the size of the range between the first threshold Th1 and the second threshold Th2. If this range is large, as shown in FIG. 4G, after another refill operation during the measurement operation, when the inventory level gradually decreases to less than or equal to the first threshold Th1, a second refill operation is initiated. If this range is small, as shown in Fig. 4H, a second recharging operation may be initiated after each measurement operation, and the first recharging operation may be ignored. It can also be considered that the first refill operation is initiated after each measurement operation, and the second refill operation is ignored, depending on which of the two recharge operations takes precedence.

Fig. 6A is a schematic diagram of an inventory level curve implemented in conjunction with the refilling method of Figs. 3B and 3X. Please refer to Figure 6A. The vertical axis in the above figure is the proportion of AgCl, the vertical axis in the middle figure is the applied measured voltage (V1) and the recharge voltage (V2), and the vertical axis in the figure below is the condition of applying a constant voltage. The measured current (without slashed area) and recharge current (with slashed area). The horizontal axis is the same time, and the vertical dashed line indicates the same point in time. If the proportion of AgCl is initially 50%, the measurement voltage of V1 is applied in the first measurement, and the proportion of AgCl gradually decreases until the measurement operation stops. Since the proportion of AgCl at this time is not less than or equal to the first threshold Th1, the recharging operation will not be started yet. Until after several measurement operations, the proportion of AgCl is less than (or equal to) the first threshold Th1, the recharging operation is started, and the recharging operation is stopped when the proportion of AgCl reaches (slightly greater than or equal to) the second threshold Th2.

Fig. 6B is a schematic diagram of another inventory level curve implemented in conjunction with the refilling method of Figs. 3B and 3X. Please refer to Figure 6B. The vertical axis in the above graph is the difference between the accumulated consumption of AgCl and the accumulated recharge (the difference is initially 0), and the vertical axis in the middle graph is the applied measured voltage (V1) and the recharge voltage (V2), the vertical axis of the figure below is the measured current (area without diagonal lines) and the recharge current (area with diagonal lines) under the condition of applying a constant voltage. The horizontal axis is the same time, and the vertical dashed line indicates the same time point. In the first measurement, the measurement voltage of V1 was applied, and the difference gradually decreased until the measurement operation was stopped. Since the difference at this time is not less than or equal to the first threshold Th1, the recharging operation will not be started yet. Until after several determination operations, the difference is less than (or equal to) the first threshold Th1, the recharging operation is started, and the recharging operation is stopped when the difference reaches (slightly greater than or equal to) the second threshold Th2.

Another embodiment of the present invention hopes to control the inventory level between Th1 and Th2, and calculate the current fluctuation amount after each measurement and immediately reclaim the secondary fluctuation amount, but the current recharge amount is not necessarily It is exactly equal to the current change amount, so there will be a change amount between each measurement and the inventory before and after each refill. However, if the single consumption is too large and is less than or equal to another lower limit threshold Th3, the inventory level can be greatly increased to Th2.

6C to 6E are graphs showing the inventory level in accordance with the embodiment of the refilling method of FIGS. 3A and 3B. For example, the curve of Fig. 6C can be controlled by the method of Fig. 3A as the main axis, Th1 and Th2 are set so that the inventory level is controlled between them, and the method shown in Fig. 3B is used, so that in case the inventory level is suddenly large When the consumption is lower than Th3, the inventory level can be effectively kept away from Th3 in the subsequent refill operation; or when the inventory level is instantly higher than Th4 due to sudden and large consumption, it can be temporarily terminated afterwards The refilling operation or reducing the refilling amount of the refilling operation effectively keeps the inventory level away from Th4.

6C, the vertical axis is the AgCl inventory level, the horizontal axis is time, S=Th2, and another lower threshold Th3 and another upper threshold Th4 are set. The refilled inventory level is initially the initial inventory level. The first refilling method shown in Figure 3A is used. After the first measurement (M1), the first refill is initiated and the first refill (R1) is implemented. The subsequent inventory The amount level has not reached S. After the second measurement (M2), the second refill (R2) and the sixth measurement (M6), the inventory level (for example, the proportion in FIG. 3B) is lower than Th3. The inventory level between R1-M6 seems to be an upward trend. In this case, it is suitable to start the second refill operation according to the method of FIG. 3B to directly increase the inventory level to S (S=Th2).

In addition, if the default value S of FIG. 3B is set to a value between Th2 and Th4, the inventory level can be increased to between Th2 and Th4. In other embodiments, other conditions that can also allow the biosensor to maintain the measurement accuracy can be selected as the default value.

Alternatively, in the method of FIG. 3B, when the inventory level reaches Th2, after the next measurement (for example, M7) is forced, if the inventory level does not reach Th3, the first step in FIG. 3A is not executed. Refill, therefore, the next step is to execute M8. If the inventory level is less than or equal to Th3, the second refill operation is forced to start again to directly increase the inventory level to S (S=Th2). The inventory level will fluctuate like the curve of M7-M8-R7-M9. If not designed in this way, the inventory level curve after M7 (not shown as M7-M9 in Figure 6C) can be similar to the change in inventory level between R1-M6, and the change in inventory level is smoother.

Please refer to FIG. 6D, which is roughly similar to FIG. 6C, except that the predetermined value S is set between I ₀ and Th2. In the same way, the inventory level can be changed between Th1 and Th2, but it is more gentle than the latter curve (M6-M9) shown in Figure 3C.

Please refer to Figure 6E. The inventory level between R3-M7 seems to be an upward trend. However, due to the setting of the thresholds Th1 and Th2, it also effectively prevents the inventory level from exceeding the upper limit.

In another embodiment, in addition to using the calculation method of the proportion or the difference, the inventory level can also be calculated by setting the threshold value (ie, the upper and lower limit) of the coulomb number of the silver halide. Referring again to Figures 3C to 3E, the inventory level is calculated based on the coulomb amount. In the case of performing a refill operation after each measurement operation, such as the curve between M1-M9, it can be clearly seen that by the method of the present invention , Even if there may be an increasing or decreasing trend during this period, the inventory level can be smoothly controlled between Th1 and Th2. Therefore, the proportion, the difference or the coulomb amount or a combination thereof can be applied to the inventory level as a measurement parameter.

Regarding the threshold application of Th3 and Th4, it may also include: when the processor confirms that the inventory level exceeds Th3 and Th4, it gives an abnormal signal, and the system can determine that the biosensor is suspended or ends the measurement operation.

Please refer to FIG. 1, when the transmission unit may optionally include a timer 260, the method of the present invention further includes the following steps: every time the fixed time interval of each measurement operation is satisfied, another recharging operation is initiated, wherein the fixed time The interval is within 15 seconds, within 30 seconds, within one minute, within ten minutes, within one hour, within two hours, within four hours, within one day, within one week or within one month.

Regarding the selection of each threshold, when the inventory level is the proportion of silver halide materials in the proportion of silver halide materials and silver materials, the first threshold Th1 is selected from 1% to 98%, and the second threshold Th2 is selected from 2. % To 99%. For example, when the first threshold Th1 is 1%, the second threshold Th2 can be a value from 2%, 3%, 4%, 5%, ... to 99%; or, when the second threshold Th2 is 99% , The second threshold Th2 can be a value of 98%, 97%, 96%, 95%, ... up to 1%, or selected from the first threshold Th1 at 20%, and the second threshold Th2 at 80%, or selected from The first threshold Th1 is at 30%, the second threshold Th2 is 70%, or the first threshold Th1 is at 40%, the second threshold Th2 is 60%, or the first threshold Th1 is at 50%, the second threshold Th2 Is 60%.

When the inventory level is the difference between the cumulative recharge amount of the silver halide material after each refill operation minus the cumulative consumption amount of the silver halide material after each measurement operation, the first threshold Th1 is -1% to -99 of the initial inventory A value between% and the second threshold Th2 is a value between 1% and 99% of the initial inventory. Wherein, the cumulative consumption may be a single consumption after only one measurement, or may be the cumulative consumption after multiple measurements.

The recharge control of the biosensor of the present invention and the method for restoring a biosensor to a proper working state can not only be applied to a biosensor having an electrode structure with a working electrode and a counter electrode, but also can be applied to a biosensor with a working electrode and a counter electrode. The biosensor with the electrode structure of the counter electrode and one auxiliary electrode; it can also be applied to the biosensor with the electrode structure of one working electrode, two counter electrodes and one auxiliary electrode; or it can also be applied to the biosensor with two working electrodes and two A biosensor of the electrode structure of the counter electrode.

The recharge control method of the biosensor of the present invention also covers the requirement of raising the inventory during the warm-up period. For example, before performing the refilling operation, it further includes the following steps: the physiological signal measuring device forcibly executes the refilling operation, and stopping the refilling operation when the inventory level increases to be greater than or equal to the second threshold Th1.

According to an embodiment of the present invention, the application of the recharge voltage is implemented by applying a fixed potential difference or a fixed current value. The fixed potential difference or a fixed current value is essentially dynamically adjusted according to the change in AgCl consumption. Detailed implementation Please refer to Figure 5 to Figure 10 for the mechanism.

According to an embodiment of the present invention, the present invention also provides a method for restoring a biosensor to a proper working state. The biosensor includes a first electrode and a counter electrode. The counter electrode includes a silver halide material and a silver material. The silver halide material has a stock In the measurement operation, the inventory level of the silver halide material is consumed. The method of the present invention includes the following steps: after the measurement operation, the change in the inventory level is calculated; and the first refill operation is initiated to recover The variation value of the replenishment inventory level, wherein the inventory level is controlled to fluctuate between the first threshold Th1 and the second threshold Th2. When the inventory level changes to less than or equal to the first threshold Th1, the first refill operation is started to refill the consumed silver halide material, so that the inventory level is increased to the first threshold Th1 and higher than the first threshold Th1 A predetermined value between the second threshold Th2.

According to an embodiment of the present invention, the method of the present invention further includes at least one of the following steps: each time the predetermined number of measurement operations is met, calculating the change value of the inventory level during the predetermined number of times, and starting The first refill operation (that is, another refill operation) is to refill the change value of the inventory level; and every time the fixed time interval of each measurement operation is met, the second refill operation is started.

According to the method of recovering silver halide of the present invention, data related to the inventory level can also be transmitted to the remote control system. The remote control system monitors the inventory level, and provides update instructions to the physiological signal measurement device when necessary to perform refilling conditions. renew.

Constant voltage voltage application

Please refer to Figures 5A-5B and 7A-7D, where Figures 5A and 5B respectively show the constant voltage circuit in the measurement mode and the recharge mode of the present invention. Figures 7A-7D show the constant voltage circuit alternately in different ways. Schematic diagram of current in measurement mode and recharge mode. The measurement mode can be started and stopped by applying the measurement potential difference V1 and removing the measurement potential difference V1, respectively, and the corresponding current is represented by Ia. In the measurement mode, the measurement potential difference V1 is applied between the working electrode W and the counter electrode R/C during the measurement period T1, so that the voltage of the working electrode W is higher than the voltage of the counter electrode R/C. As shown in Figure 5A, the switches S1 and S4 are in the closed state at this time, while the switches S2 and S3 are in the open state, the working electrode W is +Vl, and the counter electrode R/C is grounded, so that the working electrode W undergoes oxidation reaction, and The chemical reagent and the analyte are electrochemically reacted to output a physiological signal Ia, and at the same time, the AgCl of the counter electrode R/C has a consumption corresponding to the physiological signal Ia. As shown in FIGS. 7A-7D, between the plurality of measurement periods T1 is a period T2 during which no measurement is performed. In some preferred embodiments, T2 is a fixed value.

The recharging mode can be started and stopped by applying the recharging gap V2 and removing the recharging gap V2 respectively, and the corresponding current is represented by Ib. V2 is a fixed value between 0.1V and 0.8V, preferably a fixed value between 0.2V and 0.5V. In the recharge mode, apply the recharge potential V2 between the working electrode W and the counter electrode R/C for the recharge period t2 (t2 is between 0 and T2), so that the voltage of the counter electrode R/C is higher than The voltage of the working electrode W. As shown in Figure 5B, the switches S1 and S4 are in the open state at this time, while the switches S2 and S3 are in the closed state, the working electrode W is grounded, and the counter electrode R/C is +V2, so that the Ag on the counter electrode R/C The oxidation reaction proceeds, and the AgCl on the counter electrode R/C is recharged to a recharge. The recharge potential V2 in the constant voltage circuit is a fixed voltage, and the measured output current is Ib. The present invention defines the capacity of AgCl by calculating the area under the current curve (Capacity, unit coulomb, represented by the symbol "C"), so the consumption of AgCl in the measurement mode is Ia*Tl, and the recharge of AgCl in the recharge mode The amount is Ib*t2. Therefore, the recharge amount of AgCl can be controlled by regulating the application time t2 of the recharge potential V2. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

The horizontal axis in FIGS. 7A-7D represents time, the line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential difference V2. Please refer to FIG. 7A. In a preferred embodiment, V2 and T2 are both fixed values, and the application time t2 of V2 (that is, the recharging period) is a variable value. The recharge period t2 is dynamically adjusted from 0 to T2 based on the physiological signal Ia measured in the measurement mode and the measurement period T1. As shown in FIG. 7A, t2 can be t2', t2', or t2''.... In other words, the recharge period t2 can be changed according to the consumption of AgCl. If the consumption of AgCl is large, it can be recharged for a longer period of time to keep the AgCl on the counter electrode R/C within the safe inventory. For example, the amount of AgCl recharged during t2'' will be greater than the amount of AgCl recharged during t2'.

Please refer to FIG. 7B. In another preferred embodiment, V2, T2, and t2 are all fixed values, where t2=T2. In other words, the measurement mode and the recharge mode are seamlessly alternated, and the period during which no measurement is performed is the recharge period. Please refer to Figures 7C and 7D. In some preferred embodiments, V2, T2, and t2 are all fixed values, where t2 is a fixed value greater than 0 and less than T2, such as T2 = 1/2 of T2, 2/5 T2, 3/5 T2, etc. The difference between Fig. 7C and Fig. 7D is that in Fig. 7C, after each measurement mode is over, after a period of buffering time (buffer time=T2-t2), the recharge mode starts; The recharge mode starts immediately after the buffer time, and there is a period of time between the end of each recharge mode and the start of the next measurement mode. In some preferred embodiments, t2 is less than T2, and t2 can be any time period during T2.

Please refer to FIGS. 7E and 7F, which show the current schematic diagrams of the constant voltage circuit of the present invention alternately performing the measurement mode and the recharge mode in different ways. In FIGS. 7E and 7F, the horizontal axis is time and the vertical axis is current, and the curve represents the physiological parameter value curve converted from the measured physiological signal Ia. In these two embodiments, similar to FIG. 7A, V2 and T2 are fixed values, and t2 during the recharge period is a variable value. In Figures 7E and 7F, the white area under the curve represents the AgCl consumption in the measurement mode (Ia*Tl), and the oblique area represents the AgCl recharge in the recharge mode (Ib*t2). It can be seen from the figure that in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the recharge period t2 is based on the measured physiological signal Ia and the measurement period T1 and is set between 0 and T2. Dynamic adjustment between time. According to needs, the recharging mode can be selected in the front part (as shown in FIG. 7E) or the back part (as shown in FIG. 7F) of the period (T2) in which the measurement mode is not performed.

Constant current and voltage application with segment switching

Please refer to Figures 8A-8B and Figures 10A-10C, where Figures 8A and 8B respectively show the constant current circuit in the measurement mode and the recharge mode of the present invention, and Figures 10A-10C show the constant current circuit of the present invention. The current circuit alternately performs three voltage schematic diagrams of measurement mode and recharge mode in different ways. The measurement mode can be started and stopped by applying the measurement potential difference V1 and removing the measurement potential difference V1, respectively, and the corresponding current is represented by Ia. In the measurement mode, the measurement potential difference V1 is applied between the working electrode W and the counter electrode R/C for the measurement period T1. As shown in Figure 8A, the switches S1 and S4 are in the closed state at this time, while the other switches are in the open state. The working electrode W is +V1, and the counter electrode R/C is grounded, so that the working electrode W undergoes oxidation reaction and interacts with The chemical reagent and the analyte undergo an electrochemical reaction to output a physiological signal Ia, and at the same time, the AgCl of the counter electrode R/C has a consumption corresponding to the physiological signal Ia. As shown in FIGS. 10A-10C, between the plurality of measurement periods T1 is a period T2 during which no measurement is performed. In some preferred embodiments, T2 is a fixed value.

The recharging mode can be started and stopped by applying the recharging gap V2 (V2 is a variable value) and removing the recharging gap V2, and the corresponding current is represented by Ib. In the recharging mode, the recharging level difference V2 is applied between the working electrode W and the counter electrode R/C for the recharging period t2 (t2 is between 0 and T2). As shown in Figure 8B, at this time, switches S1 and S4 are in an open state, and at least one switch corresponding to S2 and I_F1 to I_Fn is in a closed state (the figure exemplarily shows that the switches corresponding to I_F1 and I_F3 are in a closed state), and work The electrode W is grounded, and the counter electrode R/C is +V2, so that the Ag on the counter electrode R/C is oxidized, and then AgCl is recharged. In the recharge mode, according to the magnitude of the physiological signal Ia and the measurement period T1, at least one switch corresponding to I_F1 to I_Fn can be selected to output a fixed current Ib, and the AgCl can be controlled by regulating the application time t2 of the potential difference V2 The amount of recharge. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

Application of constant current and voltage without segment switching

Please refer to FIGS. 9A-9B and FIGS. 10A-10C, where FIGS. 9A and 9B respectively show the stepless switching constant current circuit in the measurement mode and the recharge mode in the present invention. The measurement mode and recharge mode of this embodiment are similar to those in Figs. 8A-8B, so they will not be repeated here. The difference from the embodiment of Figs. 8A-8B is only when the embodiment is in the recharge mode, according to the physiological signal Ia A fixed current Ib is output by the control of a digital-to-analog converter (DAC), and the recharge amount of AgCl is controlled by adjusting the application time t2 of the potential difference V2. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

In FIGS. 10A-10C, the horizontal axis is time and the vertical axis is current. The line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential V2. Please refer to FIG. 10A. In a preferred embodiment, T2 is a fixed value, and the application time t2 of V2 and V2 (that is, the recharging period) is a variable value. The recharge period t2 is dynamically adjusted from 0 to T2 based on the physiological signal Ia measured in the measurement mode and the measurement period T1. As shown in FIG. 10A, t2 can be t2', t2'', or t2'''... In other words, the recharge period t2 can be changed according to the consumption of AgCl. If the consumption of AgCl is large, it can be recharged for a longer period of time to keep the AgCl on the counter electrode R/C within the safe inventory.

Please refer to FIG. 10B. In another preferred embodiment, V2 is a variable value, and T2 and t2 are both fixed values, where t2 is a fixed value greater than 0 and less than T2, such as T2 = 1/2 of T2, 2/ 5 T2, 3/7 T2, etc. In this embodiment, V2 is dynamically adjusted according to the consumption of AgCl in the physiological signal measurement step (that is, in the measurement mode). One example of the dynamic adjustment method is as follows. For example, the above-mentioned constant current circuit with segment switching is used. The circuit has n fixed current sources and n switches, and each fixed current source corresponds to a switch. In the recharge mode, according to the consumption of AgCl, at least one of the n switches is selected to be turned on (even if the switch is in a closed state) to output a fixed current value. When the recharge period t2 is a fixed value, the recharge amount of AgCl can be controlled by selecting different fixed current outputs.

Please refer to FIG. 10C. In another preferred embodiment, V2 is a variable value, and T2 and t2 are both fixed values, where t2=T2. In other words, the measurement mode and the recharge mode are seamlessly alternated, and the period during which no measurement is performed is the recharge period.

Compared with a constant current circuit with no segment switching, a constant current circuit with segment switching can control multiple current paths through multiple switches, and can recharge with a segmented constant current according to the amount of current required. The method is more power-efficient and can reduce costs. In addition, whether it is a constant voltage circuit or a constant current circuit, the potential difference can come from a DC power supply or an AC power supply.

The embodiments of FIGS. 7A to 10C describe the alternate cycle of the measurement step and the refilling step. That is, there is an AgCl refilling step between each measurement step. This method can better ensure that AgCl is kept safe. Within inventory. However, in some preferred embodiments, Y times of AgCl recharge can also be selectively matched during N measurements, where Y≤N, so that the cumulative recharge of AgCl can still be kept within the safety stock range. . The measurement step and the refilling step do not necessarily need to be performed in an alternating cycle, and the refilling step may be performed again after several measurement steps, or the refilling step may be performed only after a predetermined measurement time. For example, the refilling step can be performed again after 10 measurements, or the refilling step can be performed only after the cumulative measurement time reaches 1 hour.

Please refer to FIG. 10D, which shows a schematic diagram of the constant current circuit of the present invention alternately performing the measurement mode and the recharge mode in a manner similar to FIG. 10C. In Fig. 10D, the curve represents the physiological parameter value curve converted from the measured physiological signal Ia, and is similar to Fig. 10C, T2 and t2 are both fixed values, and V2 is a variable value. In Figure 10D, the white area under the curve represents the consumption of AgCl in the measurement mode (Ia*Tl), and the slanted area represents the recharge volume of AgCl in the recharge mode (Ib*t2). It can be seen from the figure that, in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the recharge position difference V2 is dynamically adjusted according to the consumption of AgCl.

In addition, in Figures 7E, 7F and Figure 10D, although the output timing of each physiological parameter value output after each physiological signal measurement step is performed is not shown, the physiological parameter value is not limited to the output when the measurement is completed or during the recharge period. The AgCl refilling step is not limited to being executed after each physiological parameter is output or after the physiological signal is obtained.

Please refer to FIG. 11, which shows a method for determining an analyte according to an embodiment of the present invention, by which the service life of the micro biosensor can be prolonged. The miniature biosensor may be, for example, the miniature biosensor shown in FIGS. 2A-2D, which is implanted subcutaneously to measure the physiological signal of the physiological parameter associated with the analyte in the biological fluid (for example, tissue fluid). In the embodiment of FIG. 11, the analyte may be glucose in the tissue fluid, the physiological parameter is the glucose value in the human body, and the physiological signal is the current value measured by the micro biosensor. In this embodiment, the method for measuring the analyte includes repeatedly executing the measuring step (S901) and the refilling step (S902). The measurement step (S901) includes using the aforementioned constant voltage or constant current circuit to perform the aforementioned measurement mode during the measurement period T1 to output a physiological signal (ie, current value), and at the same time, the AgCl of the counter electrode has a consumption corresponding to the current value. The measuring step (S901) further includes stopping the measuring step by stopping the aforementioned measuring mode, and the current value is calculated to output a physiological parameter (ie, a glucose value).

In the determination step (S901), the chemical reaction formula is as follows:

Perform the following oxidation reactions on the working electrode 120:

Perform the following reduction reaction on the counter electrode 130:

The recharging step (S902) includes using the aforementioned constant voltage or constant current circuit to perform the aforementioned recharging mode during the recharging period, so that the AgCl on the counter electrode has a recharging amount corresponding to the consumption, so that the AgCl on the counter electrode The amount is controlled within the safety stock range. As a result, the potential difference between the working electrode and the counter electrode can be kept stable, so that the obtained current value can still maintain a stable proportional relationship with the glucose value (if the detected substance is other analytes, it may also be proportional. It may also be an inverse relationship). In other words, it is possible to maintain a stable proportional relationship between the next current value obtained in the next measurement step and the next glucose value. The recharging step (S902) also includes stopping the recharging step by stopping the aforementioned recharging mode. After the refilling step (S902) is finished, loop back to perform the measurement step (S901) until the measurement step (S901) and the refilling step (S902) are executed N times.

In the refilling step (S902), the chemical reaction formula is as follows:

Perform the following reduction reactions on the working electrode 120:

Glucose + reduced glucose oxidase (Glucose oxidase)

The positive potential on the counter electrode 130 promotes the following oxidation reaction on the counter electrode 130:

Wherein the oxidation of the Ag electrode as Ag ^+, and from in vivo Cl ^- bonded AgCl, AgCl such that some or all of the measurement to be consumed during the period T1 is backfilled ^- Cl or AgCl after oxidation (or dissociation) To the counter electrode.

The human body can obtain chloride ions and iodide ions through iodine-doped table salt, so the available halide ions include at least chloride ions and iodide ions, which are used to recharge the silver halide.

The following embodiments are directed to the cycle of N measurement steps (S901) and N refill steps (S902), wherein the physiological parameter mentioned is preferably the glucose value, and the physiological signal mentioned is preferably the current value. According to some preferred embodiments, each measurement potential difference V1 is applied during the measurement period T1, each recharge level difference V2 is applied during the recharge period t2, and the measurement period T1 is a fixed value, which can be within 3 seconds, 5 seconds Within, within 10 seconds, within 15 seconds, within 30 seconds, within 1 minute, within 2 minutes, within 5 minutes, or within 10 minutes. According to some preferred embodiments, the time value is preferably within 30 seconds. The measurement period T1 is a fixed value, and can be 2.5 seconds, 5 seconds, 15 seconds, 30 seconds, 1 minute, 2.5 minutes, 5 minutes, 10 minutes, or 30 minutes, preferably 30 seconds. According to some preferred embodiments, each measurement period T1 plus each recharge period t2 is a fixed value. According to some preferred embodiments, each recharge level difference V2 has a fixed voltage value, and each recharge period t2 is dynamically adjusted according to each consumption of AgCl (as shown in FIG. 7A). According to some preferred embodiments, the output physiological parameters are obtained by calculating the physiological signals at a single measurement time point in each measurement period T1. According to some preferred embodiments, the output physiological parameters are obtained through a mathematical operation of a plurality of physiological signals at a plurality of measurement time points in each measurement period T1. The aforementioned mathematical operation value is, for example, the accumulated value, the average value, the median, the average value of the median, and so on. According to some preferred embodiments, by controlling the amount of each refill to be equal to or not equal to (including approximately similar, greater than or less than) each consumption, and controlling the amount of AgCl of the counter electrode within the safety stock interval, the lower The next physiological signal obtained in a determination step maintains a stable proportional relationship with the next physiological parameter. According to some preferred embodiments, the step of removing each measured potential difference V1 is to disconnect the circuit that connects the working electrode and the counter electrode, or set each measured potential difference V1 to zero. In other words, the power can be turned off to make the measuring circuit have an open state; or, a 0 volt voltage can be applied between the working electrode and the counter electrode, wherein the operation time of either of the two operations is 0.01 to 0.5 seconds. Removing the step of measuring the potential difference V1 can avoid the generation of Λ-shaped physiological signals. According to some preferred embodiments, the step of removing each regenerative level difference V2 is to disconnect the circuit that connects the working electrode and the counter electrode, or set each regenerative level difference V2 to zero.

According to some preferred embodiments, after the sensor is implanted in the human body, a warm-up time is required to allow the sensor to reach equilibrium and stability in the body in order to stably present a physiological signal that is positively correlated with the concentration of the analyte. Therefore, in the measurement step (S901), the measurement voltage is continuously applied until the end of the measurement period T1, and the measurement period T1 is controlled so that the physiological signal and the physiological parameter of the analyte reach a stable proportional relationship. Therefore, the measurement period T1 can be a variable value or a combination of a variable value and a fixed value (for example, a variable value + a fixed value. The variable value can be 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, or 24 hours. The fixed value may be, for example, 30 seconds).

Please refer to FIGS. 7A-7F, FIGS. 10A-10D and FIG. 11. The present invention uses voltage applied to the counter electrode R/C to measure the reaction current of the counter electrode in a period, and the reaction current in the period is calculated by mathematical operation. Knowing the initial capacity of AgCl, for example, by calculating the area under the reaction current curve to define the initial capacity of AgCl, also known as the initial amount or initial coulombic amount (C _initial ), the following are all explained by the amount. The counter electrode R/C contains Ag and AgCl. When the percentage of AgCl (X%AgCl) is known, the percentage of Ag can be calculated (Y%Ag=100%-X%AgCl). In each measurement step (S901), the consumption of AgCl (expressed _{as C consume} ) is defined by calculating the area under the current curve of the working electrode W. The AgCl of the counter electrode R/C has a consumption C _consume corresponding to the physiological signal Ia, that is, C _consume = Ia*T1. In each recharge step (S902), the area under the current curve of the counter electrode R/C is calculated to define the recharge amount of AgCl each time ( _{indicated by C replenish} ), that is, C _replenish = Ib*t2, and t2 is between Between 0 and T2.

The following describes the calculation method of AgCl safety stock. In some preferred embodiments, the safety stock interval is represented by the ratio of Ag to AgCl. The present invention uses the coulombic amount (C) measured on the counter electrode to reflect the ratio of Ag to AgCl. In some preferred embodiments, the ratio of Ag to AgCl is 99.9%: 0.1%, 99%: 1%, 95%: 5%, 90%: 10%, 70%: 30%, 50%: 50% , 40%:60% or 30:70%, so that AgCl has a certain amount of AgCl on the counter electrode without being exhausted, so that each physiological signal measurement step can be performed stably. The remaining amount of AgCl is the sum of the refill amount and the initial amount minus the consumption. In some preferred embodiments, the remaining amount of AgCl varies within an interval, that is, the remaining amount of AgCl is controlled within the range of the initial amount plus or minus a specific value (X value), that is, (C _replenish + C _initial )-C _consume =C _initial ±X, where 0<X<100%C _initial , 10%C _initial <X≤90%C _initial , or 0.5%C _initial <X≤50%C _initial . In some preferred embodiments, the remaining amount of AgCl may gradually decrease, gradually increase, or change steadily or arbitrarily within an interval, but still within the interval.

Please refer to FIG. 12, which shows a method for determining an analyte according to another embodiment of the present invention. By this method, the service life of the micro biosensor can be prolonged and the amount of silver and silver halide materials in the counter electrode can be reduced. The miniature biosensor may be, for example, the miniature biosensor shown in FIGS. 2A-2D, which is implanted subcutaneously to measure the physiological signal of the physiological parameter associated with the analyte in the biological fluid (for example, tissue fluid). The electrode material of the counter electrode of the micro biosensor includes silver and silver halide. In the embodiment of FIG. 12, the analyte can be glucose in tissue fluid, the physiological parameter is the glucose value in the human body, and the physiological signal is the micro biosensor. The measured current value. Only one cycle of this embodiment will be described below. The method of this embodiment starts with the following steps: applying a measuring voltage to drive the working electrode to measure a physiological signal for obtaining a physiological parameter, in which a specific amount of silver halide is consumed (hereinafter referred to as a consumption amount) (S1001).

Then stop applying the measurement voltage (S1002), and use the obtained physiological signal to obtain physiological parameters (S1003). After obtaining the physiological parameters, apply a recharge voltage between the counter electrode and the working electrode to drive the counter electrode, so that the amount of silver halide is recharged by a recharge amount (S1004), where the sum of the recharge amount and the initial amount decreases The value of the deconsumption amount (that is, the remaining amount mentioned above) is controlled within the range of the initial amount plus or minus a specific value. The above-mentioned control steps are achieved by controlling the refilling amount to be equal to or not equal to (including approximately similar, greater than or less than) the consumption, so as to maintain the amount of silver halide within the safety stock range. According to the reaction formula, the increase or decrease of the number of moles of silver halide corresponds to the increase or decrease of the number of moles of silver, so for the convenience of explanation, the consumption of silver halide corresponds to the increase of simulated silver. In some preferred embodiments, the value of the remaining amount is controlled such that the ratio of the amount of silver halide to the amount of silver plus the amount of silver halide (AgCl/Ag+AgCl) is greater than 0 and less than 1, also That is, there is only one amount of silver halide in the counter electrode, preferably between 0.01-0.99, between 0.1-0.9, between 0.2-0.8, between 0.3-0.7, or between 0.4- Between 0.6. When the recharge amount is reached, the application of the recharge voltage is stopped (S1005). Then it loops to step S1001 to execute the next loop.

A specific embodiment of the present invention will be described below. A method for calculating the size of the Ag/AgCl material of the electrode signal sensing section is taken as an example with a biosensor service life of 16 days. For example, the average measured current of the analyte for each measurement is 30 nA, the measurement period (T1) is 30 seconds, and the recharge period (t2) is 30 seconds. The daily consumption of AgCl (C _consume/day )=1.3mC/day. Assuming that the service life requirement of the sensor is 16 days, the consumption of AgCl required for 16 days is 1.3×16=20.8mC.

For example, the length of the counter electrode is 2.5mm, which corresponds to the initial amount of AgCl C _intial = 10mC;

Without performing AgCl recharging, for the sensor service life of 16 days, the required length of the counter electrode is at least:

C _16day /C _{consume/day＝} 20.8mC/1.3mg/day＝16mm

Therefore, without using the silver halide recharging method of the present invention, the length of the counter electrode needs to exceed 16 mm in order to make the sensor life up to 16 days.

In this embodiment, without using the silver halide recharging technology of the present invention, the counter electrode signal sensing section needs to be equipped with a correspondingly larger Ag/AgCl material size to achieve the sensor life of 16 days. Through the silver halide recharging method of the present invention, the silver halide recharging step is performed between the two measurement steps. The consumption and recharging of the silver halide can be repeated in a short period of time (recharge when used), so it can be reduced The amount of Ag/AgCl material in the sensor further miniaturizes the sensor, so there is no need to prepare 16 days of AgCl capacity for the electrode signal sensing section material for consumption. For example, by preparing the capacity of AgCl for about 1 to 2 days, the sensor can be used for 16 days, thereby achieving the effect of extending the service life of the sensor. The capacity of AgCl for 1 to 2 days also refers to the initial amount of AgCl in the counter electrode before leaving the factory or before performing the first measurement, for example, between about 1.3 and 2.6 mC. The initial amount can also be other smaller Or a larger range. In other embodiments, different AgCl capacities may be prepared for 1 to 5 days, 1 to 3 days, 6 to 24 hours, and 6 to 12 hours. The material size of the signal sensing section of the counter electrode only needs to have the capacity to enable the stable execution of each glucose measurement step and the positive correlation between the measurement current and the glucose concentration in the body.

If the silver chloride recharging technology of the present invention is not used, the prior art will increase the electrode length/area so that the sensor can meet the required number of days. Taking the prior art as an example, the length of the implanted end of the sensor is about 12mm. Because of the long implantation length, in order to avoid implanting deep into the subcutaneous tissue, it needs to be implanted under the skin at an oblique angle, and the implantation wound is relatively large. In addition, for example, the capacity of AgCl for 1 to 2 days is about 1.3 to 2.6 mC, and the length of the counter electrode for 1 to 2 days is 2.5 to 5 mm, which is compared with that without the silver halide of the present invention. In the case of the charging method, a length of the counter electrode of 16 mm is required, which further highlights that the present invention can effectively reduce the size of the required counter electrode. Through the silver halide refilling method of the present invention, the length of the implanted end can be shortened, for example, the length is reduced to no more than 10 mm. The lower half of the connecting area 117 to the second end 114 of the micro biosensor 100 disclosed in FIGS. 2A-2B of the present invention belong to the short implanted end 118 (as shown in FIGS. 2A and 2B), and the short implanted end 118 is implanted The penetration depth must at least meet the depth of the tissue fluid glucose that can be measured in the dermis. Through the silver halide refilling method of the present invention, the longest side of the short implant end 118 is not greater than 6 mm, so that the micro biosensor 100 can be perpendicular to the biological The method of the body surface is partially implanted under the surface of the living body. The longest side of the short implant end 118 is preferably no greater than 5 mm, 4.5 mm, 3.5 mm, or 2.5 mm. The short implant end 118 of the present invention includes the signal sensing section 132 of the counter electrode, and the longest side of the signal sensing section 132 is not greater than 6mm, preferably 2-6mm, 2-5mm, 2-4.5mm, 2- 3.5mm, 0.5-2mm, 0.2-1mm.

Therefore, compared with the case where the silver halide recharging technology of the present invention is not used, the silver halide recharging method of the present invention can effectively extend the service life of the sensor, and can greatly reduce the use of Ag/AgCl material on the counter electrode, so that The size of the counter electrode signal sensing section can be reduced. As the use of Ag/AgCl materials on the electrode is reduced, the sensor can be miniaturized and biological toxicity can be reduced. In addition, the reduction of the electrode size particularly refers to shortening the length of the implanted end of the sensor, thus reducing the pain of implantation of the user.

Example II

Please refer to FIGS. 13A and 13B, which are schematic diagrams of the front and back of the first embodiment of the micro biosensor of the present invention. The micro biosensor 300 of the present invention includes a substrate 310, a working electrode 320 disposed on the substrate 310, a counter electrode 330 and an auxiliary electrode 340, and a chemical reagent 350 surrounding the working electrode 320, the counter electrode 330 and the auxiliary electrode 340 (as shown in FIG. 13C Shown). The material of the substrate 310 can be any material that is known to be suitable for use in electrode substrates and preferably has flexibility and insulation properties, such as but not limited to polymer materials such as polyester and polyimide. The aforementioned polymer materials can be used singly or in combination of multiple types. The substrate 310 has a surface 311 (that is, the first surface), an opposite surface 312 (that is, the second surface) opposite to the surface 311, a first end 313 and a second end 314, and the substrate 310 is divided into 3 regions, which are respectively close to The signal output area 315 of the first end 313, the sensing area 316 close to the second end 314, and the connection area 317 between the signal output area 315 and the sensing area 316. The working electrode 320 is disposed on the surface 311 of the substrate 310 and extends from the first end 313 to the second end 314 of the substrate 310. The working electrode 320 includes a signal output section 321 located in the signal output area 315 of the substrate 310 and located on the substrate 310 The signal sensing section 322 of the sensing area 316.

The counter electrode 330 and the auxiliary electrode 340 are disposed on the opposite side surface 312 of the substrate 310 and extend from the first end 313 to the second end 314 of the substrate 310. The counter electrode 330 includes a signal sensing section 332 located in the sensing area 316 of the substrate 310 and the auxiliary electrode 340 includes a signal sensing section 342 located in the sensing area 316 of the substrate 310. The sensing area 316 of the micro biosensor 300 can be implanted subcutaneously so that the signal sensing section 322 measures the physiological signal associated with the analyte in the biological fluid. The physiological signal will be transmitted to the signal output section 321, and then the signal output section 321 is transmitted to the processor 210 to obtain physiological parameters. In addition to obtaining the physiological parameters from the transmission unit 200, the physiological parameters may also be transmitted to the user device 20 via wireless/wired communication, such as a smart phone, a physiological signal receiver, or a blood glucose meter.

The material on the surface of the counter electrode 330 includes silver and silver halide, and the silver halide is preferably silver chloride (Silver Chloride) or silver iodide (Silver Iodine), so that the counter electrode 330 also functions as a reference electrode That is, the counter electrode 330 of the present invention can (1) form an electronic circuit with the working electrode 320, so that the working electrode 320 is smoothly connected to ensure that the oxidation reaction occurs on the working electrode 320; and (2) provide a stable relative potential as a reference Potential. Therefore, the working electrode 320 and the counter electrode 330 of the present invention form a two-electrode system. In order to further reduce the cost and improve the biocompatibility of the biosensor of the present invention, the silver/silver halide can be mixed with carbon. For example, the silver/silver halide is mixed with carbon glue, and the silver halide content only needs to make the counter electrode 330 stable. Just execute the set measurement action. The outermost surface of the counter electrode 330 can also be covered with a conductive material to prevent silver halide from dissolution, thereby protecting the counter electrode 330. The conductive material is mainly selected from conductive materials that do not affect the measurement performance of the working electrode, such as The conductive material is Carbon.

In another embodiment of the present invention, the initial amount of silver halide may be zero before the biosensor is ready to be shipped out of the factory for sale. In this case, there is no silver halide on the counter electrode 330 of the biosensor. After the biosensor is subcutaneously implanted in the patient and during the initial recharge period before the first measurement, the silver coated on the counter electrode 330 through oxidation can be recharged with the initial amount of silver halide on the counter electrode 330 .

The auxiliary electrode 340 forms an electronic circuit with the counter electrode 330 during the recharging step, so that the counter electrode 330 is smoothly powered to ensure that the oxidation reaction occurs on the counter electrode 320. The electrode material is selected from the same material as the working electrode 320 or the same material as the working electrode 320 The working electrode 320 has a lower sensitivity to hydrogen peroxide than a material, such as carbon.

The chemical reagent 350 covers at least the

signal sensing sections

322, 332, and 342 of each electrode. In another embodiment, the chemical reagent 350 covers at least the signal sensing section 322 of the working electrode 320 (not shown in the figure). In other words, the counter electrode 330 may not be covered by the chemical reagent 350. The sensing area 316 of the micro biosensor 300 can be implanted subcutaneously so that the signal sensing section 322 of the working electrode 320 measures the physiological signal associated with the analyte in the biological fluid, and the physiological signal will be transmitted to the signal output of the working electrode 320 In section 321, the signal output section 321 transmits to the processor 210 to obtain physiological parameters. In addition to obtaining the physiological parameters from the transmission unit 200, the physiological parameters may also be transmitted to the user device 20 via wireless/wired communication for obtaining.

Please refer to FIG. 13C, which is a schematic cross-sectional view along the line AA' in FIG. In FIG. 13C, the working electrode 320 is disposed on the surface 311 of the substrate 310, the counter electrode 330 and the auxiliary electrode 340 are disposed on the opposite surface 312 of the substrate 310, and the surfaces of the working electrode 320, the counter electrode 330 and the auxiliary electrode 340 are covered with chemical reagents. 350. Basically, the chemical reagent 350 covers at least a part of the surface of the working electrode 320. The micro biosensor 300 of the present invention performs the measurement step during the measurement period, and performs the refill step during the refill period. When the measurement step is performed, the voltage of the working electrode 320 is higher than the voltage of the counter electrode 330, causing the current to flow from the working electrode 320 to the direction of the counter electrode 330, thereby causing the working electrode 320 to undergo an oxidation reaction (that is, the working electrode 320, the chemical reagent 350 and an electrochemical reaction between the analyte) is measured physiological signals, reduction reaction of the electrode 330, the counter electrode 330 so that the silver halide (AgX) consumption dissociate into silver (Ag) and a halide ion (X ^-) . Since the silver halide in the counter electrode 330 is consumed, the silver halide in the counter electrode 330 needs to be recharged to perform the next measurement step. When the recharging step is performed, the voltage of the counter electrode 330 is higher than the voltage of the auxiliary electrode 340, so that the current flows from the counter electrode 330 to the direction of the auxiliary electrode 340, and the counter electrode 330 is oxidized to cause the silver to react with the halide ions in the living body. Or combined and refilled with silver halide, the detailed measurement steps and refilling steps are shown in Figure 11.

Please refer to FIG. 14A, which is a schematic cross-sectional view of the second embodiment of the micro biosensor of the present invention. In FIG. 14A, the working electrode 320 and the auxiliary electrode 340 of the present invention may be disposed on the surface 311 of the substrate 310, the counter electrode 330 is disposed on the opposite surface 312 of the substrate 310, and the working electrode 320, the counter electrode 330 and the auxiliary electrode The surface of 340 is covered with a chemical reagent 350. In this embodiment, when the measurement step is performed, the current flows from the working electrode 320 to the counter electrode 330, and the working electrode 320 is oxidized to measure the physiological signal. The silver halide in the counter electrode 330 is consumed and dissociated. to silver (Ag) and a halide ion (X ^-). When the recharging step is performed, current flows from the counter electrode 330 to the auxiliary electrode 340, so that the counter electrode 330 undergoes an oxidation reaction to combine silver with halide ions to recharge the silver halide.

Please refer to FIG. 14B, which is a schematic cross-sectional view of the third embodiment of the micro biosensor of the present invention. In this embodiment, the micro biosensor 300 of the present invention may have two working electrodes, which are a first working electrode 323 and a second working electrode 324, respectively, and the second working electrode 324 replaces the auxiliary electrode. In FIG. 14B, the first working electrode 323 and the second working electrode 324 are provided on the surface 311 of the substrate 310, the counter electrode 330 is provided on the opposite side surface 312 of the substrate 310, and the first working electrode 323, the second working electrode 324 and the opposite The surface of the electrode 330 is covered with a chemical reagent 350. In the measuring step, the first working electrode 323 or the second working electrode 324 can be selected to measure physiological signals, and in the recharging step, the first working electrode 323 or the second working electrode 324 helps to recharge the electrode 330 with silver halide . Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 323 or the second working electrode 324 to the counter electrode 330, so that the first working electrode 323 or the second working electrode 324 is oxidized. The physiological signal is measured in response, and the silver halide in the counter electrode 330 is consumed and dissociated into silver (Ag) and halide ions (X ⁻ ). When the recharging step is performed, current flows from the counter electrode 330 to the first working electrode 323 or the second working electrode 324, so that the counter electrode 330 undergoes an oxidation reaction to combine silver with halide ions to recharge the silver halide.

Please refer to FIG. 14C, which is a schematic cross-sectional view of the fourth embodiment of the micro biosensor of the present invention. In this embodiment, the micro biosensor 300 of the present invention may have two working electrodes, which are a first working electrode 323 and a second working electrode 324, respectively, and the second working electrode 324 replaces the auxiliary electrode. In FIG. 14C, the first working electrode 323 is provided on the surface 311 of the substrate 310, the counter electrode 330 and the second working electrode 324 are provided on the opposite side surface 312 of the substrate 310, and the first working electrode 323, the second working electrode 324 and the opposite side The surface of the electrode 330 is covered with a chemical reagent 350. In this embodiment, the area of the first working electrode 323 can be increased as the electrode for measurement, and the area of the second working electrode 324 can be reduced as the electrode for recharging. Therefore, in the measurement step, the first working electrode 323 is used as the electrode. The physiological signal is measured, and during the recharging step, the second working electrode 324 helps the electrode 330 to recharge the silver halide. Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 323 to the counter electrode 330, so that the first working electrode 323 undergoes an oxidation reaction to measure physiological signals, and the halogenation in the counter electrode 330 silver is dissociated into silver (Ag) and a halide ion (X ^-) solution consumption. When the recharging step is performed, current flows from the counter electrode 330 to the second working electrode 324, so that the counter electrode 330 undergoes an oxidation reaction to combine silver with halide ions to recharge the silver halide.

Please refer to FIG. 14D, which is a schematic cross-sectional view of the fifth embodiment of the micro biosensor of the present invention. The fifth embodiment is the first embodiment with one more working electrode. That is, in the fifth embodiment, the micro biosensor 300 of the present invention has two working electrodes, the first working electrode 323 and the second working electrode 324, respectively. One counter electrode 330 and one auxiliary electrode 340. In FIG. 14D, the first working electrode 323 and the second working electrode 324 are disposed on the surface 311 of the substrate 310, the counter electrode 330 and the auxiliary electrode 340 are disposed on the opposite surface 312 of the substrate 310, and the first working electrode 323 and the second working electrode The surface of the electrode 324, the counter electrode 330, and the auxiliary electrode 340 are covered with a chemical reagent 350. In the measuring step, the first working electrode 323 or the second working electrode 324 can be selected to measure the physiological signal, and in the recharging step, the auxiliary electrode 340 helps the electrode 330 to be recharged with silver halide. Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 323 or the second working electrode 324 to the counter electrode 330, so that the first working electrode 323 or the second working electrode 324 is oxidized. The physiological signal is measured in response, and the silver halide in the counter electrode 330 is consumed and dissociated into silver (Ag) and halide ions (X ⁻ ). When the recharging step is performed, current flows from the counter electrode 330 to the auxiliary electrode 340, so that the counter electrode 330 undergoes an oxidation reaction to combine silver with halide ions to recharge the silver halide.

Please refer to FIG. 14E, which is a schematic cross-sectional view of the sixth embodiment of the micro biosensor of the present invention. In this embodiment, the micro biosensor 300 of the present invention may have three working electrodes, which are a first working electrode 323, a second working electrode 324, and a third working electrode 325, and the third working electrode 325 replaces the auxiliary electrode. In FIG. 14E, the first working electrode 323 and the second working electrode 324 are provided on the surface 311 of the substrate 310, the counter electrode 330 and the third working electrode 325 are provided on the opposite side surface 312 of the substrate 310, and the first working electrode 323 and the second working electrode The surfaces of the second working electrode 324, the third working electrode 325, and the counter electrode 330 are covered with a chemical reagent 350. In the measurement step, the first working electrode 323, the second working electrode 324, or the third working electrode 325 can be selected to measure physiological signals, and in the recharging step, the first working electrode 323 and the second working electrode 324 can also be selected. Or the third working electrode 325 helps to recharge the electrode 330 with silver halide. Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 323, the second working electrode 324, or the third working electrode 325 to the counter electrode 330, so that the first working electrode 323, the second working electrode The second working electrode 324 or the third working electrode 325 undergoes an oxidation reaction to measure physiological signals, and the silver halide in the counter electrode 330 is consumed and dissociated into silver (Ag) and halide ions (X ⁻ ). When the recharging step is performed, the current flows from the counter electrode 330 to the first working electrode 323, the second working electrode 324, or the third working electrode 325, so that the counter electrode 330 undergoes an oxidation reaction and the silver and halide ions are combined and returned. Filled with silver halide.

Please refer to FIG. 14F, which is a schematic cross-sectional view of the seventh embodiment of the micro biosensor of the present invention. The seventh embodiment is a variation of the electrode configuration of the sixth embodiment. In this embodiment, as shown in FIG. 14F, the first working electrode 323, the second working electrode 324, and the third working electrode 325 are all disposed on the surface 311 of the substrate 310, and the counter electrode 330 is disposed on the opposite surface 312 of the substrate 310. , And the surfaces of the first working electrode 323, the second working electrode 324, the third working electrode 325, and the counter electrode 330 are covered with a chemical reagent 350. In the measurement step, the first working electrode 323, the second working electrode 324, or the third working electrode 325 can be selected to measure physiological signals, and in the recharging step, the first working electrode 323 and the second working electrode 324 can also be selected. Or the third working electrode 325 helps to recharge the electrode 330 with silver halide. Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 323, the second working electrode 324, or the third working electrode 325 to the counter electrode 330, so that the first working electrode 323, the second working electrode The second working electrode 324 or the third working electrode 325 undergoes an oxidation reaction to measure physiological signals, and the silver halide in the counter electrode 330 is consumed and dissociated into silver (Ag) and halide ions (X ⁻ ). When the recharging step is performed, the current flows from the counter electrode 330 to the first working electrode 323, the second working electrode 324, or the third working electrode 325, so that the counter electrode 330 undergoes an oxidation reaction and the silver and halide ions are combined and returned. Filled with silver halide.

Please refer to FIG. 14G, which is a schematic cross-sectional view of the eighth embodiment of the micro biosensor of the present invention. Compared with FIG. 14D, the difference is that the second working electrode 324 is U-shaped. In this eighth embodiment, the first working electrode 323 and the second working electrode 324 are disposed on the surface 311 of the substrate 310, and the second working electrode 324 is adjacent to The counter electrode 330 and the auxiliary electrode 340 are disposed on the opposite side surface 312 of the substrate 310 and are arranged around the side of the first working electrode 323. In this embodiment, when the measurement step is performed, the current flows from the first working electrode 323 to the counter electrode 330, so that the first working electrode 323 undergoes an oxidation reaction to measure physiological signals, and the silver halide in the counter electrode 330 is consumed dissociate into silver (Ag) and a halide ion (X ^-). When the recharging step is performed, current flows from the counter electrode 330 to the auxiliary electrode 340 or the second working electrode 324, so that the counter electrode 330 undergoes an oxidation reaction to combine silver with halide ions to recharge the silver halide.

The detailed electrode stacks of Figures 14C-14G above are omitted, and only the electrode positions are shown.

In any of the above embodiments, the substrate 310 of the present invention is an insulator. The electrode materials of the working electrode 320 and the first working electrode 323 of the present invention include but are not limited to: carbon, platinum, aluminum, gallium, gold, indium, iridium, iron, lead, magnesium, nickel, manganese, molybdenum, osmium, palladium, Rhodium, silver, tin, titanium, zinc, silicon, zirconium, mixtures of the foregoing elements, or derivatives of the foregoing elements (such as alloys, oxides or metal compounds, etc.), preferably, the working electrode 320 and the first working electrode 323 The material is precious metal, precious metal derivative or a combination of the foregoing. More preferably, the working electrode 320 and the first working electrode 323 are made of platinum-containing materials. The second working electrode 324 and the third working electrode 325 can also use the elements or their derivatives as exemplified in the above-mentioned working electrode 320 and the first working electrode 323. In another embodiment, the electrode materials of the second working electrode 324 and the third working electrode 325 are selected from materials having a lower sensitivity to hydrogen peroxide than the first working electrode 323, such as carbon.

Since the electrode material of the counter electrode 330 of the present invention includes silver and silver halide (Ag/AgX), it has the functions of a well-known counter electrode and a reference electrode at the same time, that is, the counter electrode 330 of the present invention can be (1) formed with the working electrode 320 The electronic circuit enables the working electrode 320 to be energized smoothly to ensure that the electrochemical reaction occurs on the working electrode 320; (2) to form an electronic circuit with the auxiliary electrode 340 to make the counter electrode 330 to be energized smoothly to ensure that the oxidation reaction occurs on the counter electrode 330 And (3) provide a stable relative potential as a reference potential. Therefore, the working electrode 320, the counter electrode 330 and the auxiliary electrode 340 of the present invention form a three-electrode system which is different from the traditional three-electrode system.

When the electrode material of the auxiliary electrode 340 of the present invention is covered with platinum, the auxiliary electrode 340 can also be used as an electrode for measuring physiological signals.

In any of the above embodiments, in order to prevent the silver electrode material from being broken due to excessive chlorination, a layer of conductive material (such as carbon) may be added between the opposite surface 312 of the substrate 310 and the silver of the opposite electrode 330. However, if the bottom layer of the counter electrode 330 is carbon, the resistance at the switch will be too high. Therefore, a conductive layer, such as silver, can be added between the carbon conductive material and the opposite surface 312 of the substrate 310 to reduce the signal. The impedance of the output end makes the counter electrode 330 of the present invention form a conductive layer, a carbon layer, and a silver/silver halide layer in order from the opposite surface 312 of the substrate 310.

Constant voltage voltage application

Please refer to Figures 15A-15B and 7A-7D. Figures 15A and 15B respectively show the constant voltage circuit in the measurement mode and the recharge mode of the present invention. Figures 7A-7D show the constant voltage circuit alternately in different ways. Schematic diagram of current in measurement mode and recharge mode. The measurement mode can be started and stopped by applying the measurement potential difference V1 and removing the measurement potential difference V1, respectively, and the corresponding current is represented by Ia. In the measurement mode, the measurement potential difference V1 is applied between the working electrode W and the counter electrode R/C during the measurement period T1, so that the voltage of the working electrode W is higher than the voltage of the counter electrode R/C. As shown in Figure 15A, the switches S1 and S4 are in the closed state at this time, while the switches S2 and S3 are in the open state, the working electrode W is +Vl, the counter electrode R/C is grounded, and the auxiliary electrode Aux is in an open state to make the work The electrode W undergoes an oxidation reaction, and electrochemically reacts with the chemical reagent and the analyte to output a physiological signal Ia, and at the same time, the AgCl of the electrode R/C has a consumption amount corresponding to the physiological signal Ia. As shown in FIGS. 7A-7D, between the plurality of measurement periods T1 is a period T2 during which no measurement is performed. In some preferred embodiments, T2 is a fixed value.

The recharging mode can be started and stopped by applying the recharging gap V2 and removing the recharging gap V2 respectively, and the corresponding current is represented by Ib. V2 is a fixed value between 0.1V and 0.8V, preferably a fixed value between 0.2V and 0.5V. In the recharge mode, apply the recharge potential V2 between the counter electrode R/C and the auxiliary electrode Aux for the recharge period t2 (t2 is between 0 and T2), so that the voltage of the counter electrode R/C is higher than The voltage of the auxiliary electrode Aux. As shown in Figure 15B, the switches S1 and S4 are in an open state at this time, while the switches S2 and S3 are in a closed state, the working electrode W is in an open state, the counter electrode R/C is +V2, and the auxiliary electrode Aux is grounded to make the counter electrode The Ag on the R/C undergoes an oxidation reaction, and the AgCl on the counter electrode R/C is recharged to a recharge. The recharge potential V2 in the constant voltage circuit is a fixed voltage, and the measured output current is Ib. The present invention defines the capacity of AgCl by calculating the area under the current curve (Capacity, unit coulomb, represented by the symbol "C"), so the consumption of AgCl in the measurement mode is Ia*Tl, and the recharge of AgCl in the recharge mode The amount is Ib*t2. Therefore, the recharge amount of AgCl can be controlled by regulating the application time t2 of the recharge potential V2. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

The horizontal axis in FIGS. 7A-7D represents time, the line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential difference V2. Please refer to FIG. 7A. In a preferred embodiment, V2 and T2 are both fixed values, and the application time t2 of V2 (that is, the recharging period) is a variable value. The recharge period t2 is dynamically adjusted from 0 to T2 based on the physiological signal Ia measured in the measurement mode and the measurement period T1. As shown in FIG. 7A, t2 can be t2', t2', or t2''.... In other words, the recharge period t2 can be changed according to the consumption of AgCl. If the consumption of AgCl is large, it can be recharged for a longer time to keep the AgCl on the counter electrode R/C within the safe inventory. For example, the amount of AgCl recharged during t2'' will be greater than the amount of AgCl recharged during t2'.

Please refer to FIGS. 7E and 7F, which show the current schematic diagrams of the constant voltage circuit of the present invention alternately performing the measurement mode and the recharge mode in different ways. In FIGS. 7E and 7F, the horizontal axis is time and the vertical axis is current, and the curve represents the physiological parameter value curve converted from the measured physiological signal Ia. In these two embodiments, similar to 75A, V2 and T2 are fixed values, and t2 during recharging is a variable value. In Figures 7E and 7F, the white area under the curve represents the AgCl consumption in the measurement mode (Ia*Tl), and the oblique area represents the AgCl recharge in the recharge mode (Ib*t2). It can be seen from the figure that in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the recharge period t2 is based on the measured physiological signal Ia and the measurement period T1 and is set between 0 and T2. Dynamic adjustment between time. According to needs, the recharging mode can be selected in the front part (as shown in FIG. 7E) or the back part (as shown in FIG. 7F) of the period (T2) in which the measurement mode is not performed.

Constant current and voltage application with segment switching

Please refer to Figures 8A-8B and Figures 10A-10C, where Figures 8A and 8B respectively show the constant current circuit in the measurement mode and the recharge mode of the present invention, and Figures 10A-10C show the constant current circuit of the present invention. The current circuit alternately performs three voltage schematic diagrams of measurement mode and recharge mode in different ways. The measurement mode can be started and stopped by applying the measurement potential difference V1 and removing the measurement potential difference V1, respectively, and the corresponding current is represented by Ia. In the measurement mode, the measurement potential difference V1 is applied between the working electrode W and the counter electrode R/C for the measurement period T1. As shown in Figure 8A, the switches S1 and S4 are in the closed state at this time, and the other switches are in the open state, the working electrode W is +V1, the counter electrode R/C is grounded, and the auxiliary electrode Aux is in the open state, so that the working electrode W undergoes an oxidation reaction, and electrochemically reacts with the chemical reagent and the analyte to output a physiological signal Ia, and at the same time, the AgCl of the counter electrode R/C has a consumption amount corresponding to the physiological signal Ia. As shown in FIGS. 10A-10C, between the plurality of measurement periods T1 is a period T2 during which no measurement is performed. In some preferred embodiments, T2 is a fixed value.

The recharging mode can be started and stopped by applying the recharging gap V2 (V2 is a variable value) and removing the recharging gap V2, and the corresponding current is represented by Ib. In the recharging mode, the recharging level difference V2 is applied between the auxiliary electrode Aux and the counter electrode R/C for the recharging period t2 (t2 is between 0 and T2). As shown in Figure 8B, at this time, switches S1 and S4 are in an open state, and at least one switch corresponding to S2 and I_F1 to I_Fn is in a closed state (the figure exemplarily shows that the switches corresponding to I_F1 and I_F3 are in a closed state), and work The electrode W is in an open state, the auxiliary electrode Aux is grounded, and the counter electrode R/C is +V2, so that the Ag on the counter electrode R/C is oxidized, and then AgCl is recharged. In the recharge mode, according to the magnitude of the physiological signal Ia and the measurement period T1, at least one switch corresponding to I_F1 to I_Fn can be selected to output a fixed current Ib, and the AgCl can be controlled by regulating the application time t2 of the potential difference V2 The amount of recharge. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

Application of constant current and voltage without segment switching

Please refer to FIGS. 9A-9B and FIGS. 10A-10C, where FIGS. 9A and 9B respectively show the stepless switching constant current circuit in the measurement mode and the recharge mode in the present invention. The measurement mode and recharge mode of this embodiment are similar to those in Figs. 8A-8B, so they will not be repeated here. The difference between the embodiments of Figs. 8A-8B is only when the embodiment is in the recharge mode, according to the physiological signal Ia, The fixed current Ib is output by the control of the digital-to-analog converter (DAC), and the recharge amount of AgCl is controlled by adjusting the application time t2 of the potential difference V2. In other words, on the premise that the AgCl on the counter electrode R/C is kept within the safety inventory, the recharge amount can be made equal to or not equal to (including approximately similar, greater than or less than) the consumption.

Compared with a constant current circuit with no segment switching, a constant current circuit with segment switching can control multiple current paths through multiple switches, and can recharge with a segmented constant current according to the amount of current required. The method is more power-efficient and can reduce costs. In addition, whether it is a constant voltage circuit or a constant current circuit, the potential difference can come from a DC power source or an AC power source, preferably from a DC power source.

The examples of Figures 7A-7F, Figures 8A-8B, Figures 9A-9B, and Figures 10A-10C all describe the alternate cycle of the measurement step and the refilling step, that is, there is an AgCl return between each measurement step. In the charging step, this method can better ensure that AgCl remains within the safety stock. However, in some preferred embodiments, Y times of AgCl recharge can also be selectively matched during N measurements, where Y≤N, so that the cumulative recharge of AgCl can still be kept within the safety stock range. . The measurement step and the refilling step do not necessarily need to be performed in an alternating cycle, and the refilling step may be performed again after several measurement steps, or the refilling step may be performed only after a predetermined measurement time. For example, the refilling step can be performed again after 10 measurements, or the refilling step can be performed only after the cumulative measurement time reaches 1 hour.

Please refer to FIG. 10D, which shows a schematic diagram of the constant current circuit of the present invention alternately performing the measurement mode and the recharge mode in a manner similar to FIG. 10C. In Fig. 10D, the curve represents the physiological parameter value curve converted from the measured physiological signal Ia, and is similar to Fig. 10C, T2 and t2 are both fixed values, and V2 is a variable value. In Fig. 8D, the white area under the curve represents the consumption of AgCl in the measurement mode (Ia*Tl), and the slanted area represents the recharge of AgCl in the recharge mode (Ib*t2). It can be seen from the figure that in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the recharge position difference V2 is dynamically adjusted according to the consumption of AgCl.

In a two-electrode system including a working electrode W and a counter electrode R/C, the working electrode W must constantly switch between performing an oxidation reaction and performing a reduction reaction. In the chemical reaction environment of the electrode, the switching between oxidation and reduction reactions must go through a stabilization period, such as several seconds or minutes. In contrast, in a three-electrode system including a working electrode W, a counter electrode R/C, and an auxiliary electrode Aux, the loop between the working electrode W and the counter electrode R/C can be used to perform the measurement step, and then the auxiliary electrode Aux The circuit between the counter electrode R/C and the counter electrode R/C is recharged, thereby avoiding the disadvantage that the working electrode W needs a stabilization period, that is, the recharging step can be performed immediately after the measurement step.

Please refer to FIG. 11, which shows a method for determining an analyte according to an embodiment of the present invention, by which the service life of the micro biosensor can be prolonged. The miniature biosensor may be, for example, the miniature biosensor shown in FIGS. 13A-14, which is implanted subcutaneously to measure the physiological signal of the physiological parameter associated with the analyte in the biological fluid (for example, tissue fluid). In the embodiment of FIG. 11, the analyte may be glucose in the tissue fluid, the physiological parameter is the glucose value in the human body, and the physiological signal is the current value measured by the micro biosensor. In this embodiment, the method for measuring the analyte includes repeatedly executing the measuring step (S901) and the refilling step (S902). The measurement step (S901) includes using the aforementioned constant voltage or constant current circuit to perform the aforementioned measurement mode during the measurement period T1 to output a physiological signal (ie, current value), and at the same time, the AgCl of the counter electrode has a consumption corresponding to the current value. The measuring step (S901) further includes stopping the measuring step by stopping the aforementioned measuring mode, and the current value is calculated to output a physiological parameter (ie, a glucose value).

The following embodiments are directed to the cycle of N measurement steps (S901) and N refill steps (S902), wherein the physiological parameter mentioned is preferably the glucose value, and the physiological signal mentioned is preferably the current value. According to some preferred embodiments, each measurement potential difference V1 is applied during the measurement period T1, each recharge level difference V2 is applied during the recharge period t2, and the measurement period T1 is a fixed value, which can be within 3 seconds, 5 seconds Within, within 10 seconds, within 15 seconds, within 30 seconds, within 1 minute, within 2 minutes, within 5 minutes, or within 10 minutes. According to some preferred embodiments, the time value is preferably within 30 seconds. The measurement period T1 is a fixed value, and can be 2.5 seconds, 5 seconds, 15 seconds, 30 seconds, 1 minute, 2.5 minutes, 5 minutes, 10 minutes, or 30 minutes, preferably 30 seconds. According to some preferred embodiments, each measurement period T1 plus each recharge period t2 is a fixed value. According to some preferred embodiments, each recharge level difference V2 has a fixed voltage value, and each recharge period t2 is dynamically adjusted according to each consumption of AgCl (as shown in FIG. 7A). According to some preferred embodiments, the output physiological parameters are obtained by calculating the physiological signals at a single measurement time point in each measurement period T1. According to some preferred embodiments, the output physiological parameters are obtained through a mathematical operation of a plurality of physiological signals at a plurality of measurement time points in each measurement period T1. The aforementioned mathematical operation value is, for example, the accumulated value, the average value, the median, the average value of the median, and so on. According to some preferred embodiments, by controlling the amount of each refill to be equal to or not equal to (including approximately similar, greater than or less than) each consumption, and controlling the amount of AgCl of the counter electrode within the safety stock interval, the lower The next physiological signal obtained in a determination step maintains a stable proportional relationship with the next physiological parameter. According to some preferred embodiments, the step of removing each measured potential difference V1 is to disconnect the circuit that connects the working electrode and the counter electrode, or set each measured potential difference V1 to zero. In other words, the power can be turned off to make the measurement circuit open; or, a voltage of 0 volts can be applied between the working electrode and the counter electrode, and the operating time of either of the two operations is 0.01 to 0.5 seconds. Removing the step of measuring the potential difference V1 can avoid the generation of Λ-shaped physiological signals. According to some preferred embodiments, the step of removing each regenerative level difference V2 is to disconnect the circuit configured to connect the auxiliary electrode and the counter electrode, or to set each regenerative level difference V2 to zero.

The following describes the calculation method of AgCl safety stock. In some preferred embodiments, the safety stock interval is represented by the ratio of Ag to AgCl. The present invention uses the coulombic amount (C) measured on the counter electrode to reflect the ratio of Ag to AgCl. In some preferred embodiments, the ratio of Ag to AgCl is 99.9%: 0.1%, 99%: 1%, 95%: 5%, 90%: 10%, 70%: 30%, 50%: 50% , 40%:60% or 30:70%, so that AgCl has a certain amount of AgCl on the counter electrode without being exhausted, so that each physiological signal measurement step can be performed stably. The remaining amount of AgCl is the sum of the refill amount and the initial amount minus the consumption. In some preferred embodiments, the remaining amount of AgCl varies within an interval, that is, the remaining amount of AgCl is controlled within the range of the initial amount plus or minus a specific value (X value), namely (C _replenishe + C _initial )-C _consume =C _initial ±X, where 0<X<100%C _initial , 10%C _initial <X≤90%C _initial , or 0.5%C _initial <X≤50%C _initial . In some preferred embodiments, the remaining amount of AgCl may gradually decrease, gradually increase, or change steadily or arbitrarily within an interval, but still within the interval.

Please refer to FIG. 11, which shows a method for determining an analyte according to another embodiment of the present invention, by which the service life of the micro biosensor can be prolonged and the amount of silver and silver halide materials for the counter electrode can be reduced. The miniature biosensor can be, for example, the miniature biosensor shown in FIGS. 13A-13C and 14A-14G, which is implanted subcutaneously to measure the physiological parameters associated with the analyte in the biological fluid (for example, tissue fluid). Signal. The electrode material of the counter electrode of the micro biosensor includes silver and silver halide. In the embodiment of FIG. 11, the analyte can be glucose in tissue fluid, the physiological parameter is the glucose value in the human body, and the physiological signal is the micro biosensor. The measured current value. Only one cycle of this embodiment will be described below. The method of this embodiment starts with the following steps: applying a measuring voltage to drive the working electrode to measure a physiological signal for obtaining a physiological parameter, in which a specific amount of silver halide is consumed (hereinafter referred to as a consumption amount) (S1001).

Then stop applying the measurement voltage (S1002), and use the obtained physiological signal to obtain physiological parameters (S1003). After obtaining the physiological parameters, apply a recharge voltage between the counter electrode and the auxiliary electrode to drive the counter electrode, so that the amount of silver halide is recharged by a recharge amount (S1004), where the sum of the recharge amount and the initial amount decreases The value of the deconsumption amount (that is, the remaining amount mentioned above) is controlled within the range of the initial amount plus or minus a specific value. The above-mentioned control steps are achieved by controlling the refilling amount to be equal to or not equal to (including approximately similar, greater than or less than) the consumption, so as to maintain the amount of silver halide within the safety stock range. According to the reaction formula, the increase or decrease of the number of moles of silver halide corresponds to the increase or decrease of the number of moles of silver, so for the convenience of explanation, the consumption of silver halide corresponds to the increase of simulated silver. In some preferred embodiments, the value of the remaining amount is controlled such that the ratio of the amount of silver halide to the amount of silver plus the amount of silver halide (AgCl/Ag+AgCl) is greater than 0 and less than 1, also That is, there is only one amount of silver halide in the counter electrode, preferably between 0.01-0.99, between 0.1-0.9, between 0.2-0.8, between 0.3-0.7, or between 0.4- Between 0.6. When the recharge amount is reached, the application of the recharge voltage is stopped (S1005). Then it loops to step S1001 to execute the next loop.

C _16day /C _{consume/day＝} 20.8mC/1.3mg/day＝16mm

If the silver chloride recharging technology of the present invention is not used, the prior art will increase the electrode length/area to make the sensor reach the required number of days. Taking the prior art as an example, the sensor implantation end length is about 12mm. The implantation length is long, and in order to avoid implanting deep into the subcutaneous tissue, it needs to be implanted under the skin at an oblique angle, and the implantation wound is relatively large. In addition, for example, the capacity of AgCl for 1 to 2 days is about 1.3 to 2.6 mC, and the length of the counter electrode for 1 to 2 days is 2.5 to 5 mm, which is compared with that without the silver halide of the present invention. In the case of the charging method, a length of the counter electrode of 16 mm is required, which further highlights that the present invention can effectively reduce the size of the required counter electrode. Through the silver halide refilling method of the present invention, the length of the implanted end can be shortened, for example, the length is reduced to no more than 10 mm. In the micro biosensor 300 of the present invention, the lower half of the connection area 317 to the second end 314 belong to the short implant end 318 (as shown in FIGS. 13A and 13B), and the implant depth of the short implant end 318 must be at least The dermis layer can measure the depth of tissue fluid glucose, so the longest side of the short implanted end 318 is not greater than 6 mm, so that the micro biosensor 300 can be partially implanted under the epidermis of the organism in a manner perpendicular to the epidermis of the organism. The longest side of the short implant end 318 is preferably no more than 5 mm, 4.5 mm, 3.5 mm, or 2.5 mm. The short implanted end of the present invention includes the signal sensing section 332 of the counter electrode 330, and the longest side of the signal sensing section 332 is not greater than 6mm, preferably 2-6mm, 2-5mm, 2-4.5mm or 2-3.5 mm, 0.5-2mm, 0.2-1mm.

Example III

Please refer to FIGS. 18A and 18B, which are schematic diagrams of the front and back of the first embodiment of the micro biosensor of the present invention. The micro biosensor 400 of the present invention includes a substrate 410, a first working electrode 420, a second working electrode 430, a first pair of electrodes 440 and a second pair of electrodes 450, and surrounding the first working electrode 420, a The two working electrodes 430, the first pair of electrodes 440 and the second pair of electrodes 450 are chemical reagents 460 (as shown in FIG. 18C). The material of the substrate 410 can be any material that is known to be suitable for use in electrode substrates and preferably has flexibility and insulation properties, such as but not limited to polymer materials such as polyester and polyimide. The aforementioned polymer materials can be used singly or in combination of multiple types. The substrate 410 has a surface 411 (that is, the first surface), an opposite surface 412 (that is, the second surface) opposite to the surface 411, a first end 413 and a second end 414, and the substrate 410 is divided into 3 regions, which are respectively close to The signal output area 415 of the first end 413, the sensing area 416 close to the second end 414, and the connection area 417 between the signal output area 415 and the sensing area 416. The first working electrode 420 and the second working electrode 430 are disposed on the surface 411 of the substrate 410 and extend from the first end 413 to the second end 414 of the substrate 410. The first working electrode 420 includes a first signal output section 421 located in the signal output area 415 of the substrate 410 and a first signal sensing section 422 located in the sensing area 416 of the substrate 410. The second working electrode 430 includes a second signal output section 431 located in the signal output area 415 of the substrate 410 and a second signal sensing section 432 located in the sensing area 416 of the substrate 410.

The first pair of electrodes 440 and the second pair of electrodes 450 are disposed on the opposite side surface 412 of the substrate 410 and extend from the first end 413 to the second end 414 of the substrate 410. The first pair of electrodes 440 includes a third signal output section 441 located in the signal output area 415 of the substrate 410, and a third signal sensing section 442 located in the sensing area 416 of the substrate 410, and the second pair of electrodes 450 includes a third signal output section 441 located on the substrate 410. The fourth signal output section 451 of the signal output area 415 and the fourth signal sensing section 452 of the sensing area 416 of the substrate 410 are located. The materials on the surfaces of the first pair of electrodes 440 and the second pair of electrodes 450 include silver and silver halide, and the silver halide is preferably silver chloride (Silver Chloride) or silver iodide (Silver Iodine). The counter electrode 440 and the second pair of electrodes 450 both have the functions of reference electrodes, that is, the first pair of electrodes 440 and the second pair of electrodes 450 of the present invention can (1) form an electronic circuit with the first working electrode 420 or the second working electrode 430 , Enabling the first working electrode 420 or the second working electrode 430 to be smoothly energized to ensure that the oxidation reaction occurs on the first working electrode 420 or the second working electrode 430; and (2) providing a stable relative potential as a reference potential. Therefore, the first working electrode 420, the second working electrode 430, the first pair of electrodes 440, and the second pair of electrodes 450 of the present invention form a four-electrode system. In order to further reduce the cost and improve the biocompatibility of the biosensor of the present invention, the silver/silver halide can be mixed with carbon. For example, the silver/silver halide is mixed into the carbon glue, and the silver halide content is as long as the first pair of electrodes 440 And the second pair of electrodes 450 can perform the set measurement operation stably. The surface of the first pair of electrodes 440 and the second pair of electrodes 450 may also be covered with conductive materials to prevent silver halide from dissolution, thereby protecting the first pair of electrodes 440 and the second pair of electrodes 450, wherein the conductive material is The conductive material that does not affect the measurement performance of the working electrode is mainly selected, for example, the conductive material is Carbon.

In another embodiment of the present invention, the initial amount of silver halide may be zero before the biosensor is ready to be shipped out of the factory for sale. In this case, there is no silver halide on the first pair of electrodes 440 and/or the second pair of electrodes 450 of the biosensor. After the biosensor is subcutaneously implanted in the patient's body and during the initial recharging period before the first measurement, the silver coated on the first pair of electrodes 440 and/or the second pair of electrodes 450 through oxidation may be in the first pair of electrodes. The pair of electrodes 440 and/or the second pair of electrodes 450 are refilled with the initial amount of silver halide.

The chemical reagent 460 at least covers the first signal sensing section 422 of the first working electrode 420. In another embodiment, the chemical reagent 460 covers at least the first signal sensing section 422 and the second signal sensing section 432 of the first working electrode 420 and the second working electrode 430. In another embodiment, the chemical reagent 460 covers the

signal sensing sections

422, 432, 442, and 452 of all electrodes. In another embodiment, the first pair of electrodes 440 and/or the second pair of electrodes 450 may not be covered by the chemical reagent 460. The sensing area 416 of the micro biosensor 400 can be implanted subcutaneously so that the first signal sensing section 422 and the second signal sensing section 432 perform the determination of the physiological signals associated with the analyte in the biological fluid, and the physiological signals will be transmitted separately The first output section 421 and the second output section 431 of the signal are transmitted to the processor 210 from the first output section 421 and the second output section 431 to obtain physiological parameters. In addition to obtaining the physiological parameters from the transmission unit 200, the physiological parameters may also be transmitted to the user device 20 via wireless/wired communication, such as a smart phone, a physiological signal receiver, or a blood glucose meter.

Please refer to FIG. 18C, which is a schematic cross-sectional view along the line AA' in FIG. In FIG. 18C, the first working electrode 420 and the second working electrode 430 are disposed on the surface 411 of the substrate 410, the first pair of electrodes 440 and the second pair of electrodes 450 are disposed on the opposite surface 412 of the substrate 410, and the first working electrode 420 The surfaces of the second working electrode 430, the first pair of electrodes 440 and the second pair of electrodes 450 are covered with a chemical reagent 460. Basically, the chemical reagent 460 covers at least a part of the surface of a working electrode. The micro biosensor 400 of the present invention will perform the measurement step during the measurement period and perform the refill step during the refill period. In the measuring step, the first working electrode 420 or the second working electrode 430 can be selected to measure physiological signals, and in the recharging step, the first working electrode 420 or the second working electrode 430 helps the first pair of electrodes 440 or the second electrode Two pairs of electrodes 450 are recharged with silver halide. Therefore, in this embodiment, when the measurement step is performed, the voltage of the first working electrode 420 or the second working electrode 430 is higher than the voltage of the first pair of electrodes 440 or the second pair of electrodes 450, so that the current flows from the first working electrode. 420 or the second working electrode 430 flows in the direction of the first pair of electrodes 440 or the second pair of electrodes 450, thereby causing the first working electrode 420 or the second working electrode 430 to undergo an oxidation reaction (that is, the first working electrode 420 or the second working electrode 430). The electrochemical reaction between the electrode 430, the chemical reagent 460 and the analyte) to measure the physiological signal, the first pair of electrodes 440 or the second pair of electrodes 450 undergo a reduction reaction, so that the first pair of electrodes 440 or the second pair of electrodes 450 silver halide consumed dissociate into silver (Ag) and a halide ion (X ^-). Since the silver halide in the first pair of electrodes 440 or the second pair of electrodes 450 is consumed, it is necessary to recharge the silver halide in the first pair of electrodes 440 or the second pair of electrodes 450 to perform the next measurement step. When the recharging step is performed, the voltage of the first pair of electrodes 440 or the second pair of electrodes 450 is higher than the voltage of the first working electrode 420 or the second working electrode 430, so that the current flows from the first pair of electrodes 440 or the second pair of electrodes 450 Flow in the direction of the first working electrode 420 or the second working electrode 430, and then cause the first pair of electrodes 440 or the second pair of electrodes 450 to oxidize to combine silver and halide ions to recharge the silver halide. Detailed measurement steps and recharge The steps are illustrated in Figure 12.

Please refer to FIG. 19A, which is a schematic cross-sectional view of the second embodiment of the micro biosensor of the present invention. The second embodiment is a change of the electrode configuration of the first embodiment. In this embodiment, as shown in FIG. 19A, the first working electrode 420 and the first pair of electrodes 440 of the micro biosensor 400 of the present invention are disposed on the surface 411 of the substrate 410, and the second working electrode 430 and the second pair of electrodes 450 The opposite side surface 412 of the substrate 410 is provided, and the surface of the first working electrode 420, the second working electrode 430, the first pair of electrodes 440, or the second pair of electrodes 450 is covered with a chemical reagent 460. Similarly, in the measuring step, the first working electrode 420 or the second working electrode 430 can be selected to measure physiological signals, and in the recharging step, the first working electrode 420 or the second working electrode 430 can also be selected to help The pair of electrodes 440 or the second pair of electrodes 450 are backfilled with silver halide. Therefore, in this embodiment, when the measurement step is performed, the current flows from the first working electrode 420 or the second working electrode 430 to the first pair of electrodes 440 or the second pair of electrodes 450, so that the first working electrode 420 Or the second working electrode 430 undergoes an oxidation reaction to measure physiological signals, and the first pair of electrodes 440 or the second pair of electrodes 450 undergo a reduction reaction, so that the silver halide in the first pair of electrodes 440 or the second pair of electrodes 450 is consumed and dissociated into silver (Ag) and a halide ion (X ^-). When the recharging step is performed, the current flows from the first pair of electrodes 440 or the second pair of electrodes 450 to the direction of the first working electrode 420 or the second working electrode 430, thereby causing the first pair of electrodes 440 or the second pair of electrodes 450 to generate The oxidation reaction combines silver and halide ions to recharge the silver halide.

Please refer to FIG. 19B, which is a schematic cross-sectional view of the third embodiment of the micro biosensor of the present invention. In the third embodiment, the first working electrode 420 of the micro biosensor 400 of the present invention is arranged on the surface 411 of the substrate 410, and the second working electrode 430, the first pair of electrodes 440, and the second pair of electrodes 450 are arranged on the surface of the substrate 410. The side surface 412, and the surface of the first working electrode 420, the second working electrode 430, the first pair of electrodes 440, or the second pair of electrodes 450 are covered with a chemical reagent 460. The second working electrode 430 can be arranged between the two opposite electrodes, and can also be arranged at the leftmost or rightmost position (not shown in the figure). In this embodiment, in the measuring step, the first working electrode 420 or the second working electrode 430 can be selected to measure physiological signals, and in the recharging step, the first working electrode 420 or the second working electrode can also be selected 430 helps to recharge the first pair of electrodes 440 or the second pair of electrodes 450 with silver halide.

Please refer to FIG. 19C, which is a schematic cross-sectional view of the fourth embodiment of the micro biosensor of the present invention. In the fourth embodiment, the first working electrode 420 and the second working electrode 430 of the micro biosensor 400 of the present invention are disposed on the surface 411 of the substrate 410, and the second working electrode 430 is U-shaped and is adjacently disposed and surrounds the first working electrode. On the side of a working electrode 420, the first pair of electrodes 440 and the second pair of electrodes 450 are disposed on the opposite side surface 412 of the substrate 410, and the first working electrode 420, the second working electrode 430, the first pair of electrodes 440 and the second The surfaces of the two pairs of electrodes 450 are covered with a chemical reagent 460. In this embodiment, in the measurement step, the first working electrode 420 or the second working electrode 430 can be selected to measure physiological signals, and in the recharging step, the first working electrode 420 or the second working electrode 430 can also be selected. It helps to recharge the first pair of electrodes 440 or the second pair of electrodes 450 with silver halide.

The detailed electrode stacks of Figures 18C-19C above are omitted, and only the electrode positions are shown. The above FIGS. 18C-19C basically cover the surface of the first working electrode 420 with the chemical reagent 460 at least.

In any of the above embodiments, the materials of the first working electrode 420 and the second working electrode 430 include but are not limited to: carbon, platinum, aluminum, gallium, gold, indium, iridium, iron, lead, magnesium, nickel, manganese, Molybdenum, osmium, palladium, rhodium, silver, tin, titanium, zinc, silicon, zirconium, mixtures of the foregoing elements, or derivatives of the foregoing elements (such as alloys, oxides or metal compounds, etc.), preferably, the first work The materials of the electrode 420 and the second working electrode 430 are precious metals, derivatives of precious metals, or a combination of the foregoing. More preferably, the first working electrode 420 and the second working electrode 430 are platinum-containing materials. In another embodiment, the electrode material of the second working electrode 430 is selected from a material having a lower sensitivity to hydrogen peroxide than that of the first working electrode 420, such as carbon.

In any of the above embodiments, in order to prevent the silver electrode material from being disconnected due to excessive chlorination, it is also possible to add one between the opposite side surface 412 of the substrate 410 and the silver of the first pair of electrodes 440 and the second pair of electrodes 450. Layer of conductive material (such as carbon). However, if the bottom layer of the first pair of electrodes 440 and the second pair of electrodes 450 is carbon, the resistance at the switch will be too high. Therefore, a layer of conductive material can be added between the carbon conductive material and the opposite surface 412 of the substrate 410. The layer, such as silver, is used to reduce the impedance of the signal output terminal, so that the first pair of electrodes 440 and the second pair of electrodes 450 of the present invention start from the opposite side surface 412 of the substrate 410 as a conductive layer, a carbon layer, and a silver/silver halide layer in order .

Since the micro biosensor 400 of the present invention has two working electrodes and two counter electrodes, the micro biosensor 400 can use, for example, the first working electrode 420 and the first pair of electrodes 440 to perform the measurement step while using the second working electrode. 430 and the second pair of electrodes 450 perform a recharging step. Or, for example, the first working electrode 420 is used to continuously perform the measurement step, while the second working electrode 430 is used to help the first pair of electrodes 440 or the second pair of electrodes 450 perform the recharging step.

Constant voltage voltage application

Please refer to FIGS. 20A-20C, which respectively show the constant voltage circuit in the present invention that can perform the measurement mode and the recharge mode according to different methods. The measurement mode can be started and stopped by applying the measurement potential difference V1 and removing the measurement potential difference V1, respectively, and the corresponding current is represented by Ia. In the constant voltage circuit, the first working electrode W1 is controlled by switch S1, the first pair of electrodes R/C1 is controlled by switches S5 and S6, the second working electrode W2 is controlled by switches S2 and S7, and the second The counter electrode R/C2 is controlled by switches S3 and S4. With the above-mentioned switch control, there are many flexible operation modes, as shown in the following example.

As shown in FIG. 20A, in the measurement mode, the measurement potential difference V1 is applied between the first working electrode W1 and the first pair of electrodes R/C1 during the measurement period T1, so that the voltage of the first working electrode W1 is higher than that of the first pair of electrodes. Voltage of electrode R/C1. At this time, the switches S1 and S6 are in the closed state, and the switch S5 is in the open state. The first working electrode W1 is +Vl, and the first pair of electrodes R/C1 is grounded, so that the first working electrode W1 undergoes oxidation reaction and reacts with chemical reagents. Electrochemically reacts with the analyte to output a physiological signal Ia, and at the same time, the AgCl of the first pair of electrodes R/C1 has a consumption corresponding to the physiological signal Ia. In the recharging mode, it can be started and stopped by applying the recharging gap V2 and removing the recharging gap V2 respectively, and the corresponding current is represented by Ib. V2 is a fixed value between 0.1V and 0.8V, preferably a fixed value between 0.2V and 0.5V. In the recharge mode, apply the recharge potential V2 between the second working electrode W2 and the second pair of electrodes R/C2 for the recharge period t2, so that the voltage of the second pair of electrodes R/C2 is higher than that of the second working electrode The voltage of W2. At this time, the switches S4 and S7 are in the open state, and the switches S2 and S3 are in the closed state. The second pair of electrodes R/C2 is +V2, and the second working electrode W2 is grounded, so that the Ag on the second pair of electrodes R/C2 The oxidation reaction is carried out, and the AgCl on the second pair of electrodes R/C2 is recharged to a recharge amount. The recharge potential V2 in the constant voltage circuit is a fixed voltage, and the measured output current is Ib. The present invention defines the capacity of AgCl by calculating the area under the current curve (Capacity, unit coulomb, represented by the symbol "C"), so the consumption of AgCl in the measurement mode is Ia*Tl, and the recharge of AgCl in the recharge mode The amount is Ib*t2. Therefore, the recharge amount of AgCl can be controlled by regulating the application time t2 of the recharge potential V2. In other words, under the premise that the AgCl on the first or second pair of electrodes R/C1 or R/C2 is kept within the safety inventory, the recharge amount can be equal to or not equal to (including approximately similar, greater than or less than) consumption quantity. Figure 20A illustrates that the timing of the simultaneous measurement mode and the timing of the recharge mode overlap. The above-mentioned switch control can also be changed to other forms of circuits to have a variety of flexible operation modes. In some preferred embodiments, the measurement The mode sequence and the recharge mode sequence can be carried out at the same time, and can also be partially overlapped or not overlapped.

Figures 20B-20C are similar to Figure 20A, the only difference is that Figure 20B shows an embodiment using W2 and R/C2 for measurement and W1 and R/C1 for refilling; and Figure 20C shows an embodiment using W1 and R /C2 is measured and W2 and R/C1 are used for refilling. In some preferred embodiments, the constant voltage circuit alternately switches to FIG. 20A and FIG. 20B and repeats the cycle. In some preferred embodiments, the constant voltage circuit alternately switches to FIG. 20A and FIG. 20C and repeats the cycle. In the above manner, the first pair of electrodes R/C1 and the second pair of electrodes R/C2 can be consumed and recharged in turn, so that the AgCl on the two pairs of electrodes can be kept within the safe inventory. In some preferred embodiments, the constant voltage circuit may have a third voltage source to control the recharge voltage difference to be different from the measured voltage difference.

By controlling the application of the voltage difference and the switching of the switch, the constant voltage circuit shown in Figs. 20A-20C can also alternately perform the measurement mode and the recharge mode. 7A-7D respectively show the current schematic diagrams of the constant voltage circuit alternately performing the measurement mode and the recharge mode in different ways. As shown in the figure, between a plurality of measurement periods T1 is a period T2 during which no measurement is performed. In some preferred embodiments, T2 is a fixed value. The horizontal axis in FIG. 7A7D represents time, the line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential difference V2. Please refer to FIG. 7A. In a preferred embodiment, V2 and T2 are both fixed values, and the application time t2 of V2 (that is, the recharging period) is a variable value. The recharge period t2 is dynamically adjusted from 0 to T2 based on the physiological signal Ia measured in the measurement mode and the measurement period T1. As shown in FIG. 7A, t2 can be t2', t2', or t2''.... In other words, the recharge period t2 can be changed according to the consumption of AgCl. If the consumption of AgCl is large, it can be recharged for a longer time to keep the AgCl on the first pair of electrodes R/C1 within the safe inventory. For example, the amount of AgCl recharged during t2'' will be greater than the amount of AgCl recharged during t2'.

Please refer to FIGS. 7E and 7F, which show the current schematic diagrams of the constant voltage circuit of the present invention alternately performing the measurement mode and the recharge mode in different ways. In FIGS. 7E and 7F, the horizontal axis is time and the vertical axis is current, and the curve represents the physiological parameter value curve converted from the measured physiological signal Ia. In these two embodiments, similar to FIG. 7A, V2 and T2 are fixed values, and t2 during the recharge period is a variable value. In Figures 7E and 7F, the white area under the curve represents the AgCl consumption in the measurement mode (Ia*Tl), and the oblique area represents the AgCl recharge in the recharge mode (Ib*t2). It can be seen from the figure that, in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the refill period t2 is based on the measured physiological signal Ia and the measurement period T1 and is set between 0 and T2. Dynamic adjustment between time. According to needs, the recharging mode can be selected in the front part (as shown in FIG. 7E) or the back part (as shown in FIG. 7F) of the period (T2) in which the measurement mode is not performed.

Constant current and voltage application with segment switching

Please refer to FIG. 21, which shows a constant current circuit capable of segmented switching between the measurement mode and the recharge mode in the present invention. The method of the constant current circuit with segment switching to repeat the measurement mode and the recharge mode is similar to that of FIG. 20A, so it will not be repeated here. The main difference is that the recharging mode can be started and stopped by applying the recharging gap V2 (V2 is a variable value) and removing the recharging gap V2, and the corresponding current is represented by Ib. Taking the recharging mode executed on the second working electrode W2 and the second pair of electrodes R/C2 as an example, the recharging potential V2 is applied between the second working electrode W2 and the second pair of electrodes R/C2 for the recharging period t2 . At this time, the switches S2 and S3 are in the closed state, the switch S2 and at least one switch corresponding to I_F1 to I_Fn in the partial constant current circuit 61 are in the closed state, the second working electrode W2 is grounded, and the second pair of electrodes R/C2 is + V2, so that the Ag on the second pair of electrodes R/C2 undergoes an oxidation reaction, and AgCl is backfilled. The constant current circuit with segment switching in this embodiment can selectively switch to I_F1, I_F2, I_F3...I_Fn by controlling multiple switches corresponding to I_F1 to I_Fn to adjust the required recharge level difference V2 and output the current Ib. In the recharging mode, the recharging amount of AgCl can be controlled by adjusting the recharging level difference V2 and its application time t2 according to the magnitude of the physiological signal Ia and the measurement period T1. In other words, under the premise that the AgCl on the first or second pair of electrodes R/C1 or R/C2 is kept within the safety inventory, the recharge amount can be equal to or not equal to (including approximately similar, greater than or less than) consumption quantity. In another embodiment, part of the constant current circuit 61 may be configured to connect to the second pair of electrodes R/C2.

Application of constant current and voltage without segment switching

Please refer to FIG. 22, which shows a constant current circuit capable of stepless switching between the measurement mode and the recharge mode in the present invention. The measurement mode of the constant current circuit with stepless switching is similar to that of Figs. 20A-20C, and the recharging mode is similar to that of Fig. 21, so it will not be repeated here. The difference between the embodiment of FIG. 22 and FIG. 21 is only that in the constant current circuit of FIG. 22, the part of the constant current circuit 71 with stepless switching is controlled by a digital-to-analog converter (DAC) to output a fixed current Ib.

Please refer to FIGS. 10A-10C, which show the voltage schematic diagrams of the constant current circuit of the present invention alternately performing the measurement mode and the recharge mode in different ways. The horizontal axis in FIGS. 10A-10C represents time, the line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential difference V2. Please refer to FIG. 10A. In a preferred embodiment, T2 is a fixed value, and the application time t2 of V2 and V2 (that is, the recharging period) is a variable value. The recharge period t2 is dynamically adjusted from 0 to T2 based on the physiological signal Ia measured in the measurement mode and the measurement period T1. As shown in FIG. 10A, t2 can be t2', t2'', or t2'''... In other words, the recharge period t2 can be changed according to the consumption of AgCl. If the consumption of AgCl is large, it can be recharged for a longer time to keep the AgCl on the first pair of electrodes R/C1 within the safe inventory.

Compared with a constant current circuit with no segment switching, a constant current circuit with segment switching can control multiple current paths through multiple switches, and can recharge with a segmented constant current according to the amount of current required. The method is more power-efficient and can reduce costs. In addition, whether it is a constant voltage circuit or a constant current circuit, the potential difference can come from a DC power source or an AC power source, preferably a DC power source.

The embodiments of Figures 7A-7F, Figures 21-22, and Figures 10A-10C all describe the alternate cycle of the measurement step and the refilling step, that is, there is an AgCl refilling step between each measurement step. This method It can better ensure that AgCl remains within the safety stock. However, in some preferred embodiments, Y times of AgCl recharge can also be selectively matched during N measurements, where Y≤N, so that the cumulative recharge of AgCl can still be kept within the safety stock range. . The measurement step and the refilling step do not necessarily need to be performed in an alternating cycle, and the refilling step may be performed again after several measurement steps, or the refilling step may be performed only after a predetermined measurement time. For example, the refilling step can be performed again after 10 measurements, or the refilling step can be performed only after the cumulative measurement time reaches 1 hour.

Please refer to FIG. 10D, which shows a schematic diagram of the constant current circuit of the present invention alternately performing the measurement mode and the recharge mode in a manner similar to FIG. 10C. In FIG. 10D, the curve represents the physiological parameter value curve converted into the measured physiological signal Ia, and similar to FIG. 10C, T2 and t2 are both fixed values, and V2 is a variable value. In Figure 10D, the white area under the curve represents the consumption of AgCl in the measurement mode (Ia*Tl), and the slanted area represents the recharge volume of AgCl in the recharge mode (Ib*t2). It can be seen from the figure that in order to make Ib*t2 close to Ia*Tl or within a certain range of Ia*Tl, the recharge position difference V2 is dynamically adjusted according to the consumption of AgCl.

In the foregoing embodiment in which the constant current or constant voltage circuit of the present invention is used to alternately perform the measurement mode and the recharge mode, the working electrodes used in the measurement mode and the recharge mode can be the first working electrode W1 and the second working electrode W1. For any of the electrodes W2, the counter electrode used in the measurement mode can also be either the first pair of electrodes R/C1 and the second pair of electrodes R/C2, but the counter electrode used in the recharge mode Preferably, it is the counter electrode used in the previous measurement mode. Two exemplary embodiments are described below. Example 1 is carried out in chronological order: (a) use W1/W2 (representing one of W1 and W2) and R/C1 measurement, (b) use the other W1/W2 and R/C1 recharge, (c) Use one of W1/W2 and R/C2 to measure, (d) use the other W1/W2 and R/C2 to recharge, repeat steps (a)-(d). In Embodiment 2, steps (a), (b), (a), (b), (c), (d), (c), (d) are repeatedly executed in chronological order.

Please refer to FIGS. 23A and 23B, which show schematic diagrams of different embodiments in which the constant current or constant voltage circuit of the present invention performs the measurement mode and the recharge mode at the same time. The horizontal axis in FIGS. 23A and 23B is time, the line of V1 represents the application and removal of the measured potential difference V1, and the line of V2 represents the application and removal of the recharge potential difference V2. Since there are two counter electrodes and two working electrodes in the present invention, the measuring step and the recharging step can be performed at the same time. In the embodiment of FIG. 23A, the first combination formed by the first working electrode W1 and the first pair of electrodes R/C1 and the second combination formed by the second working electrode W2 and the second pair of electrodes R/C2 alternately perform measurement and return. Filling steps. That is, when the first combination is used for the measurement step, the second combination is used for the refill step, and vice versa. In the embodiment of FIG. 23B, the first working electrode W1 is fixed for the measuring step, the second working electrode W2 is fixed for the recharging step, and the two counter electrodes are used alternately between the measuring step and the recharging step. In some preferred embodiments, multiple T1s do not overlap with each other. In some preferred embodiments, multiple t2s do not overlap with each other. In some preferred embodiments, T1 and t2 overlap (meaning that they start and end at the same time) or partially overlap. Figures 23A and 23B show that the first measurement (using R/C1) is not accompanied by the refilling step, and the second measurement (using R/C2) is performed at the same time (refilling R/C1). However, it can also be accompanied by the refilling step (refilling R/C2) at the first measurement (using R/C1).

Please refer to FIG. 11, which shows a method for determining an analyte according to an embodiment of the present invention, by which the service life of the micro biosensor can be prolonged. The miniature biosensor can be, for example, the miniature biosensor shown in FIGS. 18A-18C and 19A-19C, which is used to be implanted subcutaneously to measure the physiological parameters associated with the analyte in the biological fluid (for example, tissue fluid). Signal. In the embodiment of FIG. 9, the analyte may be glucose in tissue fluid, the physiological parameter is the glucose value (or concentration) in the human body, and the physiological signal is the current value measured by the micro biosensor. In this embodiment, the method for measuring the analyte includes repeatedly executing the measuring step (S901) and the refilling step (S902). The measurement step (S901) includes using the aforementioned constant voltage or constant current circuit to perform the aforementioned measurement mode during the measurement period T1 to output a physiological signal (i.e., current value), and at the same time, the AgCl of the counter electrode has a consumption amount corresponding to the current value. The measurement step (S901) also includes stopping the measurement mode as described above.

The following embodiments are directed to the cycle of N measurement steps (S901) and N refill steps (S902), wherein the physiological parameter mentioned is preferably the glucose value, and the physiological signal mentioned is preferably the current value. According to some preferred embodiments, each measurement potential difference V1 is applied during the measurement period T1, each recharge level difference V2 is applied during the recharge period t2, and the measurement period T1 is a fixed value, which can be within 3 seconds, 5 seconds Within, within 10 seconds, within 15 seconds, within 30 seconds, within 1 minute, within 2 minutes, within 5 minutes, or within 10 minutes. According to some preferred embodiments, the time value is preferably within 30 seconds. According to some preferred embodiments, the measurement period T1 is a fixed value, and can be 2.5 seconds, 5 seconds, 15 seconds, 30 seconds, 1 minute, 2.5 minutes, 5 minutes, 10 minutes or 30 minutes, preferably 30 seconds . According to some preferred embodiments, each measurement period T1 plus each recharge period t2 is a fixed value. According to some preferred embodiments, each recharge level difference V2 has a fixed voltage value, and each recharge period t2 is dynamically adjusted according to each consumption of AgCl (as shown in FIG. 7A). According to some preferred embodiments, the output physiological parameters are obtained by calculating the physiological signals at a single measurement time point in each measurement period T1. According to some preferred embodiments, the output physiological parameters are obtained through a mathematical operation of a plurality of physiological signals at a plurality of measurement time points in each measurement period T1. The aforementioned mathematical operation value is, for example, the accumulated value, the average value, the median, the average value of the median, and so on. According to some preferred embodiments, by controlling the amount of each refill to be equal to or not equal to (including approximately similar, greater than or less than) each consumption, and controlling the amount of AgCl of the counter electrode within the safety stock interval, the lower The next physiological signal obtained in a determination step maintains a stable proportional relationship with the next physiological parameter. According to some preferred embodiments, the step of removing each measured potential difference V1 is to disconnect the circuit that connects the working electrode and the counter electrode, or set each measured potential difference V1 to zero. In other words, the power can be turned off to make the measuring circuit have an open state; or, a 0 volt voltage can be applied between the working electrode and the counter electrode, wherein the operation time of either of the two operations is 0.01 to 0.5 seconds. Removing the step of measuring the potential difference V1 can avoid the generation of Λ-shaped physiological signals. According to some preferred embodiments, the step of removing each regenerative level difference V2 is to disconnect the circuit that connects the working electrode and the counter electrode, or set each regenerative level difference V2 to zero.

According to some preferred embodiments, after the sensor is implanted in the human body, a warm-up time is required to allow the sensor to reach equilibrium and stability in the body in order to stably present a physiological signal that is positively correlated with the concentration of the analyte. Therefore, in the measurement step (S901), the measurement voltage is continuously applied until the measurement period T1 ends, and the measurement period T1 is controlled so that the physiological signal and the physiological parameter of the analyte reach a stable proportional relationship. Therefore, the measurement period T1 can be a variable value or a combination of a variable value and a fixed value (for example, a variable value + a fixed value. The variable value can be 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, or 24 hours. The fixed value may be, for example, 30 seconds).

The following describes the calculation method of AgCl safety stock. In some preferred embodiments, the safety stock interval is represented by the ratio of Ag to AgCl. The present invention uses the coulombic amount (C) measured on the counter electrode to reflect the ratio of Ag to AgCl. In some preferred embodiments, the ratio of Ag to AgCl is 99.9%: 0.1%, 99%: 1%, 95%: 5%, 90%: 10%, 70%: 30%, 50%: 50% , 40%: 60% or 30: 70%, so that AgCl has a certain amount on the counter electrode without being exhausted, so that each physiological signal measurement step can be performed stably. The remaining amount of AgCl is the sum of the refill amount and the initial amount minus the consumption. In some preferred embodiments, the remaining amount of AgCl varies within an interval, that is, the remaining amount of AgCl is controlled within the range of the initial amount plus or minus a specific value (X value), that is, (C _replenish + C _initial )-C _consume =C _initial ±X, where 0<X<100%C _initial , 10%C _initial <X≤90%C _initial , or 0.5%C _initial <X≤50%C _initial . In some preferred embodiments, the remaining amount of AgCl may gradually decrease, gradually increase, or change steadily or arbitrarily within an interval, but still within the interval.

Please refer to FIG. 12, which shows a method for determining an analyte according to another embodiment of the present invention. By this method, the service life of the micro biosensor can be prolonged and the amount of silver and silver halide materials in the counter electrode can be reduced. The miniature biosensor can be, for example, the miniature biosensor shown in FIGS. 18A-18C and 19A-19C, which is used to be implanted subcutaneously to measure the physiological parameters associated with the analyte in the biological fluid (for example, tissue fluid). Signal. The electrode material of the counter electrode of the micro biosensor includes silver and silver halide. In the embodiment of FIG. 12, the analyte can be glucose in tissue fluid, the physiological parameter is the glucose value in the human body, and the physiological signal is the micro biosensor. The measured current value. Only 2 cycles of this embodiment are described below. The method of this embodiment starts with the following steps: during the first measurement period, the measurement voltage is applied to drive the first or second working electrode W1/W2 to measure the physiological signal used to obtain the physiological parameter, wherein the first or second pair of electrodes The silver halide of R/C1 or R/C2 (assuming the first pair of electrodes R/C1) is consumed by a consumption amount (S1101).

Then, the application of the measurement voltage is stopped (S1102), and the obtained physiological signal is used to obtain the physiological parameter (S1103). After the physiological parameters are obtained, the recharge voltage is applied during the first recharge period to drive the counter electrode used in S1101 with the consumption (ie the first pair of electrodes R/C1), so that the amount of silver halide is recharged. The recharge amount (S1104), wherein the value of the sum of the recharge amount and the initial amount minus the consumption amount (that is, the remaining amount mentioned above) is controlled within the range of the initial amount plus or minus a specific value. The above-mentioned control steps are achieved by controlling the refilling amount to be equal to or not equal to (including approximately similar, greater than or less than) the consumption, so as to maintain the amount of silver halide within the safety stock range. According to the reaction formula, the increase or decrease of the number of moles of silver halide corresponds to the increase or decrease of the number of moles of silver, so for the convenience of explanation, the consumption of silver halide corresponds to the increase of simulated silver. In some preferred embodiments, the value of the remaining amount is controlled such that the ratio of the amount of silver halide to the amount of silver plus the amount of silver halide (AgCl/Ag+AgCl) is greater than 0 and less than 1, also That is, there is only one amount of silver halide in the counter electrode, preferably between 0.01-0.99, between 0.1-0.9, between 0.2-0.8, between 0.3-0.7, or between 0.4- Between 0.6. When the recharge amount is reached, the application of the recharge voltage is stopped (S1105). Then return to step S1101. During the second measurement period, the measurement voltage is applied to drive the first or second working electrode W1/W2 to measure another physiological signal for obtaining another physiological parameter, and the other counter electrode (ie The silver halide of the second pair of electrodes R/C2) is consumed by a consumption amount. Then, the application of the measurement voltage is stopped (S1102), and the obtained physiological signal is used to obtain the physiological parameter (S1103). After the physiological parameters are obtained, the recharge voltage is applied during the second recharge period to drive the counter electrode used in S1101 with the consumption (ie the second pair of electrodes R/C2), so that the amount of silver halide is recharged. Recharge amount (S1104). Then it loops to step S1001 to execute the next loop.

C _16day /C _{consume/day＝} 20.8mC/1.3mg/day＝16mm

If the silver chloride recharging technology of the present invention is not used, the prior art will increase the electrode length/area so that the sensor can meet the required number of days. Taking the prior art as an example, the length of the implanted end of the sensor is about 12mm. Due to the long implantation length, in order to avoid implanting deep into the subcutaneous tissue, it needs to be implanted under the skin at an oblique angle, and the implantation wound is relatively large. In addition, for example, the capacity of AgCl for 1 to 2 days is about 1.3 to 2.6 mC, and the length of the counter electrode for 1 to 2 days is 2.5 to 5 mm, which is compared with that without the silver halide of the present invention. In the case of the charging method, a length of the counter electrode of 16 mm is required, which further highlights that the present invention can effectively reduce the size of the required counter electrode. Through the silver halide refilling method of the present invention, the length of the implanted end can be shortened, for example, the length is reduced to no more than 10 mm. The lower half of the connection area 417 of the micro biosensor 400 disclosed in FIGS. 18A-18C of the present invention to the second end 414 belong to the short implanted end 418 (as shown in FIGS. 18A and 18B), and the short implanted end 418 is implanted The penetration depth must be at least the depth of the tissue fluid glucose that can be measured in the dermis. Through the silver halide refilling method of the present invention, the longest side of the short implant end 418 is not more than 6 mm, so that the micro biosensor 400 can be perpendicular to the biological The method of the body surface is partially implanted under the surface of the living body. The longest side of the short implant end 418 is preferably no greater than 5 mm, 4.5 mm, 3.5 mm, or 2.5 mm. The short implanted end 418 of the present invention includes a third signal sensing section 442 and a fourth signal sensing section 452, and the longest side of the third signal sensing section 442 and the fourth signal sensing section 452 is not greater than 6 mm, which is relatively Preferably they are 2-6mm, 2-5mm, 2-4.5mm, 2-3.5mm, 0.5-2mm, 0.2-1mm.

Therefore, compared with the case where the silver halide recharging technology of the present invention is not used, the silver halide recharging method of the present invention can effectively extend the service life of the sensor, and can greatly reduce the use of Ag/AgCl material on the counter electrode, so that The size of the counter electrode signal sensing section can be reduced. As the use of Ag/AgCl materials on the electrode is reduced, the sensor can be miniaturized and biological toxicity can be reduced. In addition, the reduction of the electrode size particularly refers to shortening the length of the implanted end of the sensor, thus reducing the pain of implantation of the user. In the device of the present invention including four electrodes, since measurement and recharging can be performed at the same time, it can have a shorter counter electrode size and a more flexible and efficient operation mode than a device including two electrodes or three electrodes.

Reduce the size of the counter electrode

In order to reduce the size of the counter electrode, the amount of silver halide on the counter electrode can be minimized to an initial amount sufficient to support at least one measurement of the biosensor. The size of the counter electrode is quantified based on the initial amount of silver halide, which is sufficient to process at least one determination of the physiological signal of the physiological parameter related to the analyte in the patient. After the first measurement, the silver halide that was consumed during the refill period was refilled. Therefore, the present invention provides a method for determining the size of the counter electrode of a biosensor and for extending the lifespan of the biosensor.

Fig. 24 is a flowchart according to an embodiment of the present invention. As shown in FIG. 24, the method includes the following steps: Step a: Define a required consumption range of the silver halide during the measurement period performed by the biosensor at least once; Step b: According to the required consumption range An upper limit plus a buffer amount determines the initial amount, so that a required recharge amount range of the silver halide during the regeneration period is controlled to be sufficient to maintain an amount of the silver halide within a safety stock interval To ensure that a second physiological signal obtained during a second measurement period after the regeneration period maintains a stable proportional relationship with a second physiological parameter; step c: converting the initial quantity to the size of the pair of electrodes; Step d: Make the pair of electrodes contain at least the initial amount of the silver halide; Step e: Measure the physiological signal during the measurement period and the silver halide is consumed by a consumption amount; and Step f: During the regeneration period the silver halide It is recharged once.

According to an embodiment of the present invention, before the biosensor is ready to be sold out of the factory, an initial amount of silver halide is prepared. The silver halide layer can be printed with an initial amount on the counter electrode or a silver layer coated on the counter electrode via halogenation so that it has an initial amount of silver halide.

In another embodiment of the present invention, the initial amount of silver halide may be zero before the biosensor is ready to be shipped out of the factory for sale. In this case, there is no silver halide on the counter electrode of the biosensor. After the biosensor is subcutaneously implanted in the patient's body and during the initial recharging period before the first measurement, the silver coated on the counter electrode through oxidation can be recharged with the initial amount of silver halide on the counter electrode.

Generally, when a biosensor is implanted in a patient, the possible trauma to the skin and/or subcutaneous tissue sometimes causes the signal monitored by the sensor to be unstable. In addition, before using the biosensor, the biosensor must be completely "moistened" or hydrated to achieve a balance with the analyte in the patient (for example, glucose in the biological fluid). Therefore, after the biosensor is implanted in the organism, the user must wait for a warm-up period before the initial measurement of the biosensor in order to obtain an accurate reading of the analyte concentration. In this case, since the biosensor needs a warm-up period before measuring the analyte after being implanted in the organism, the initial recharge period can be performed in the warm-up period without delaying any required measurement.

In order to understand how to determine the initial amount of silver halide, the following is an example of a calculation method that defines the required consumption range of silver halide by performing at least one physiological signal measurement period on the physiological sensor. The physiological parameters of the analyte are correlated. Taking the glucose measurement in the human body and the silver halide as a silver chloride as an example, a predetermined upper limit of the detected glucose concentration is selected as the reference, for example, it is performed once when the glucose concentration is 600 mg/dL Physiological signal measurement to obtain the required consumption current is 100nA per second. If the measurement period lasts for 30 seconds, the required consumption of silver chloride during a measurement period is 3000nC (or 0.003mC), which is 100nA multiplied by 30 seconds acquired. In this case, the upper limit of the consumption of silver chloride required for one measurement can be selected to be greater than or equal to 0.003 mC. In other embodiments, other concentration values can be selected for the upper limit value.

Because the analyte concentration of different patients or the concentration of the same patient at different times may fluctuate to a large extent and the internal environment is variable, it is recommended to use a larger range of silver halide consumption (that is, the need Larger initial amount), so the required silver halide consumption range must also be added with a buffer amount to cope with the fluctuation of the analyte concentration in the patient's body so as to keep the silver halide in a safe inventory at the counter electrode during the measurement process. Changes within the interval, so that the measured physiological signals and physiological parameters maintain a stable proportional relationship. The amount of buffering can be greater than 0, and can be adjusted based on the predetermined period of use of the biosensor. The time of the scheduled use period can be any multiple of the time of the measurement period, such as 1, 2, 4, 10, 100 times, etc., or an appropriate scheduled use period is selected according to the sensor, such as 1 hour, 2 hours, 6 hours , 1 day, 2 days, 3 days, 5 days, etc. to prepare a sufficient but small initial amount.

In addition to the required consumption range, in addition to selecting one measurement as the calculation basis, you can also select multiple measurement periods to adjust the required consumption range according to the expected use period of the biosensor, and the corresponding buffering amount also follows the required consumption. The range is adjusted to adjust the initial amount of silver halide required.

In another embodiment of the present invention, the arithmetic mean, geometric mean, or median of the required consumption range can also be used to replace the upper limit of the required consumption range to determine the initial amount, which depends on the biosensor's possibility. The actual situation faced. For example, it is known that the average current of the physiological signal measured by the biosensor in a measurement is 20nA per second. If the measurement period lasts for 30 seconds, the average consumption of silver chloride during a measurement period is 600nC (or 0.0006). mC), which is obtained by multiplying 20nA by 30 seconds. In this case, the average consumption of silver chloride required for one measurement can be determined to be 0.0006mC.

Since it is also necessary to consider the analyte concentration of different patients or the concentration of the same patient at different times may fluctuate to a large extent and the internal environment may vary, it is recommended to use a larger range of silver halide consumption ( That is, a larger initial amount is required). For example, if the measurement period is performed every 1 minute, and a measurement lasts for 30 seconds, 1440 measurements are required a day, so the required silver chloride consumption is 0.864mC, which is The value obtained by multiplying 0.0006 mC by 1440 times per day is close to 1 mC, so a value within 1 mC can be selected as the buffer amount to determine the initial amount of silver chloride.

In the above embodiment, the required silver halide consumption range and buffer amount can be adjusted based on the predetermined use period of the biosensor. The time of the scheduled use period can be any multiple of the time of the measurement period, such as 1, 2, 4, 10, 100 times, etc., or an appropriate scheduled use period is selected according to the sensor, such as 1 hour, 2 hours, 6 hours , 1 day, 2 days, 3 days, 5 days, etc. to prepare a sufficient but small initial amount.

Since the current required for each biosensor to perform a measurement depends on the design and characteristics of the biosensors produced by different manufacturers, the consumption range of the required silver halide also depends on different biosensors. Therefore, it can be understood that any modification to the required consumption is within the scope of the present invention.

In addition to the required silver halide consumption range, a buffer can also be added to cope with fluctuations in the analyte concentration in the patient's body. The amount of buffering can be greater than 0, and can be adjusted based on the predetermined period of use of the biosensor. The required consumption can be adjusted according to multiple measurement times during the predetermined use period of the biosensor.

The initial amount can be determined based on the upper limit of the required consumption range and the sum of the buffer amount to ensure that the required recharge amount of silver halide during the recharge period is sufficient to keep the amount of silver halide within a safe inventory range to safely Ensure that the next physiological signal and the next physiological parameter are successfully obtained during the next measurement period and maintain a stable proportional relationship between the two. In the case of controlling the refilling amount of silver halide to be sufficient to support the consumption in the next measurement, the buffering amount may be zero.

If the upper limit of the required silver chloride consumption range is selected as 1mC, and the buffer amount is selected as 0.5mC, the initial amount of silver chloride on the counter electrode can be determined as 1.5mC, which is the sum of 1mC and 0.5mC . Therefore, the required recharge amount range can be greater than zero, greater than 1.5 mC, or less than 1.5 mC.

Based on the initial amount of silver halide, at least the first measurement can be made. After performing the first measurement, perform the first recharge to recharge the consumed silver halide.

After deciding the initial amount, the required size of the counter electrode is thus decided. The size of the counter electrode is related to the total volume of silver and silver halide on the counter electrode. The initial amount of silver halide can be converted into the total volume of silver halide on the counter electrode. The total volume of silver and silver halide can be simply defined by the arithmetic product of the width, length, and thickness of silver and silver halide on the counter electrode. Any of the width, length, and thickness can be adjusted to change the volume of silver and silver halide. Generally, the width and thickness of the silver and silver halide on the counter electrode are predetermined to meet the constraints of design and manufacturing capabilities. Therefore, the volume of silver and silver halide on the counter electrode can be reduced by reducing the length of the silver and silver halide on the counter electrode, which means that the length of the counter electrode can be shortened. Therefore, by using the method for determining the initial amount of silver halide provided by the present invention, a biosensor with a prolonged service life and a shorter counter electrode can be realized. Therefore, the patient's pain and discomfort for the implanted biosensor will be greatly reduced, and there is no need to frequently purchase new biosensors to replace old biosensors.

According to an embodiment of the present invention, when the initial amount of silver halide used for a day is 1.5 mC, the unit amount (or unit capacity) of silver halide depending on the characteristics of the biosensors of different manufacturers is 300 mC/mm ³ In this case, the required silver halide volume is 0.005 mm ³ . When the width of the counter electrode is 0.3 mm and the thickness of the silver halide is 0.01 mm, the length of the silver halide on the counter electrode is 1.67 mm. Proportionally, if the required initial amount of silver halide requires 3.6 days, the length of the silver halide, that is, the length of the counter electrode is about 6mm, if the required initial amount of silver halide requires 6 days, the counter electrode The length is about 10mm. Because the length of the counter electrode can be shortened, the length of the biosensor implanted in the patient can be correspondingly shortened, and the biosensor can also be implanted vertically in the patient to minimize damage to the patient. Therefore, not only can the life of the biosensor be prolonged due to the recharge period provided by the present invention, but also the pain and discomfort caused to the patient can be reduced due to the shortened length of the counter electrode.

Of course, reducing the volume of silver and silver halide can be achieved by changing at least one of the length, width, and thickness of silver and silver halide. All the above modifications are still within the scope of the present invention.

Through the recharging method of the present invention and the setting of the first threshold and the second threshold in an appropriate interval, the silver halide can be performed without waiting for the silver halide depletion signal to appear (for example, when the physiological signal appears noise) Recharge to control the inventory level of silver halide within this threshold range. The use of the predetermined value S can further help control the inventory level after silver halide refilling within a specific range of preference. Moreover, with the recharging method of the present invention, the recharging rate of silver chloride does not have to be completely positively correlated with the decrease rate of silver chloride during the measurement, and it is not necessary to refill the silver chloride immediately after each measurement.

The present invention is also applicable to biosensors with any number of counter electrodes and any number of working electrodes, such as a biosensor with one working electrode, one auxiliary electrode and one counter electrode, and a biosensor with two working electrodes and one counter electrode. , Or a biosensor with two working electrodes and two counter electrodes. If the biosensor has two or more counter electrodes, all counter electrodes may have the same size and/or the same initial amount of silver halide.

Although the present invention has been described in terms of what is currently considered to be the most practical and preferred embodiment, it should be understood that the present invention is not limited to the disclosed embodiment. On the contrary, its intent is to cover various modifications and similar configurations included in the spirit and scope of the scope of the appended patent application. These modifications and similar arrangements should be consistent with the broadest interpretation to cover all such modifications and Similar structure.

【Symbol Description】

10: Physiological signal measuring device

20: User device

61: Partial constant current circuit with segment switching

71: Partial constant current circuit with stepless switching

100, 300, 400: Miniature biosensor

110, 310, 410: substrate

111, 311, 411: Surface

112, 312, 412: Opposite side surface

113, 313, 413: the first end

114, 314, 414: second end

115, 315, 415: signal output area

116, 316, 416: sensing area

117, 317, 417: connection area

120, 320: working electrode

121, 321: signal output section

122, 322, 332, 342: signal sensing section

130, 330: Counter electrode

131: Signal output section

132: Signal sensing section

140, 350, 460: chemical reagents

200: Transmission unit

210: Processor

220: power supply

230: Voltage applying unit

240: Temperature sensing unit

250: Communication unit

260: Timer

318, 418: Short implant end

323, 420: the first working electrode

324, 430: second working electrode

325: Third working electrode

340: auxiliary electrode

321: The first signal output section

322: The first signal sensing section

431: The second signal output section

432: The second signal sensing section

440: The first pair of electrodes

441: The third signal output section

442: The third signal sensing section

450: The second pair of electrodes

451: The fourth signal output section

452: The fourth signal sensing section

I0: initial quantity

M1, M2, M3, M4, M5, M6, M7, M8, M29: measurement operation

R1, R2, R3, R4, R5, R6, R7, R8: recharge operation

N: Number of measurements

P: scheduled times

S: predetermined value

S1, S2, S3, S4, S5, S6, S11, S12, S13, S14, S15, S16, S21, S22, S23, S24, S25, S26, S31, S32, S33, S34, S35, S36, S37, S38, S41, S42, S43, S44, S45, S46, S47, S48, S51, S52, S53, S54, S55, S56, S57, S58, S901, S902, S1001, S1002, S1003, S1004, S1005 steps

Th1, Th3: the first threshold

Th2, Th4: second threshold

Claims

A method for controlling the recharge of silver halide material in a biosensor, the biosensor being used to implant subcutaneously to measure the physiological signal of the physiological parameter associated with the analyte in the biological fluid, and the biosensor is at least It includes a first electrode and a counter electrode. The counter electrode includes a silver halide material and a silver material. The silver halide material has an inventory level in the silver halide material and the silver material. The recharge control method includes the following step:

After the measurement operation, obtain the measurement value of the physiological signal, wherein the inventory level decreases after the measurement operation;

Every time the predetermined number of measurement operations is met, the change value of the inventory level during the predetermined number of times is calculated, and the first refill operation is initiated to refill the inventory level. The variation value, the predetermined number of times is a positive integer,

The inventory level basically varies between the first threshold and the second threshold.
The refill control method according to claim 1, further comprising the step of: when the inventory level is less than or equal to the first threshold, a second refill operation is initiated until the inventory level increases A predetermined value between the first threshold or the second threshold greater than the first threshold.
The recharge control method according to claim 2, further comprising the step of: when the inventory level is greater than or equal to the second threshold, the second recharge operation is no longer performed or the second recharge operation is reduced. The number of second refill operations or the refill amount until the inventory level decreases to the predetermined value.
2. The recharge control method according to claim 2, further comprising the step of: starting the second recharge operation every time when the fixed time interval of each of the measurement operations is satisfied.
The recharge control method of claim 3, wherein the fixed time interval is within 15 seconds, within 30 seconds, within one minute, within ten minutes, within one hour, within two hours, within four hours, within one day, A time value within a week or a month.
The method of recharging control according to claim 1, wherein when the inventory level is the proportion of the silver halide material in the silver halide material and the silver material, the first threshold is selected from 1. % To 98%, and the second threshold is selected from 2% to 99%.
The method of recharging control according to claim 1, wherein when the inventory level is the cumulative recharging amount of the silver halide material after each recharging operation minus the silver halide material after each measuring operation When the difference in the cumulative consumption of materials is the value, the first threshold is a value between -1% and -99% of the initial inventory, and the second threshold is a value between 1% and -99% of the initial inventory. Values between 99%.
The recharge control method of claim 1, wherein the recharge method is implemented by applying a recharge voltage between the counter electrode and the first electrode, and the first electrode is a working electrode , Or the biosensor includes an auxiliary electrode, which is implemented by applying a recharge voltage between the counter electrode and the auxiliary electrode.
8. The recharge control method of claim 8, wherein applying the recharge voltage is implemented by applying a fixed potential difference or a fixed current value.
The method for controlling the recharging of claim 1, wherein before performing the recharging operation, the method further comprises the following steps:

The recharging operation is forcibly performed by the physiological signal measuring device; and

Stop the refill operation when the inventory level increases to be greater than or equal to the second threshold.
A physiological signal measuring device that can control the inventory level of silver halide materials of a biosensor. The silver halide material has an initial inventory level, and the inventory level represents the inventory level of the silver halide material at the time and is applied The physiological signal measuring device is caused to perform a refill operation to restore the silver halide material to the inventory level, and the physiological signal measuring device includes:

The biosensor includes:

The first electrode, and

The first pair of electrodes includes the silver halide material and the silver material; and

The transmission unit is coupled to the biosensor and includes:

The processor is configured to reduce the consumption of the inventory when the measurement operation is started, increase the inventory by the refill when the refill operation is started, and calculate the inventory level,

The processor controls the inventory level to substantially vary between a first threshold and a second threshold.
The physiological signal measurement device of claim 11, wherein when the processor determines that the inventory level is less than or equal to a first threshold, the processor causes the physiological signal measurement device to perform the refilling Operation to increase the inventory level to a predetermined value between the first threshold and a second threshold greater than the first threshold.
The physiological signal measurement device according to claim 12, wherein when the processor determines that the inventory level is greater than or equal to the second threshold, the number of recharging operations or the recharging amount is no longer executed or reduced , Until the inventory level decreases to a predetermined value between the first threshold and the second threshold.
The physiological signal measurement device according to claim 11, further comprising a voltage applying unit, which is controlled by the processor to perform the measurement operation on the biosensor to obtain the physiological signal and perform the recharging Operate to restore the inventory level.
11. The physiological signal measuring device according to claim 11, wherein the recharging operation is performed by the voltage applying unit applying a recharging voltage between the first pair of electrodes and the first electrode, and The first electrode is a working electrode.
The physiological signal measurement device of claim 11, wherein the biosensor further comprises an auxiliary electrode, and the recharging operation is performed by the voltage applying unit applying a recharging voltage to the first pair of electrodes and the Implemented between the auxiliary electrodes.
The physiological signal measurement device of claim 11, wherein the biosensor further comprises a second pair of electrodes and a second electrode, and the measurement operation is performed by the voltage applying unit applying a measurement voltage to the One of the first electrode and the second working electrode is implemented between one of the first pair of electrodes and the second pair of electrodes, and the recharging operation is applied by the voltage applying unit. It is implemented by pressing between the other of the first pair of electrodes and the second pair of electrodes and the other of the first electrode and the second electrode.
The physiological signal measurement device according to claims 15-17, wherein the application of the recharge voltage is implemented by applying a fixed potential difference or a fixed current value, and the fixed potential difference or a fixed current value is essentially It is dynamically adjusted according to changes in consumption.
The physiological signal measurement device according to claim 11, wherein the recovery time and the recovery amount of the inventory level when the processor performs the refill operation can be based on the total consumption of each measurement operation performed Or the average consumption, the cumulative consumption of each measurement operation in a period of time, and the natural consumption of the silver halide material or a combination thereof are dynamically adjusted.
11. The physiological signal measuring device according to claim 11, wherein the biosensor is implanted subcutaneously in a living body.
A method for restoring a biosensor to a proper working state. The biosensor includes a first electrode and a counter electrode. The counter electrode includes a silver halide material and a silver material. The silver halide material has an inventory level and is under measurement. During operation, the inventory level of the silver halide material is consumed, and the method includes the following steps:

After the measurement operation, calculate the change in the inventory level; and initiate a first refill operation to refill the change value of the inventory level,

The inventory level is controlled to fluctuate between the first threshold and the second threshold.
The method of claim 21, when the inventory level changes to be less than or equal to the first threshold, a recovery operation is initiated to refill the consumed silver halide material, so that the inventory level Raise to a predetermined value between the first threshold and a second threshold higher than the first threshold.
The method of claim 21, further comprising at least one of the following steps:

Every time the predetermined number of measurement operations is satisfied, calculate the change value of the inventory level during the predetermined number of times, and start the first refill operation to refill the inventory Said variation of the level; and

Each time the fixed time interval of each measurement operation is satisfied, the second recharging operation is started.