JP4595070B2 - Needle integrated biosensor - Google Patents

Description

  The present invention relates to a needle-integrated biosensor. More particularly, the present invention relates to a needle-integrated biosensor having a configuration in which a puncture needle for piercing the skin to obtain blood and a biosensor for collecting and analyzing body fluid taken on the surface of the skin are integrated.

Conventionally, a diabetic patient himself collects blood and measures a blood glucose level which is a glucose level in blood. In this case, the patient uses a blood collection device called a lancet that attaches and detaches the blood collection needle. is doing. In such a measurement method, the patient must carry a set of measuring instruments consisting of several points, such as a blood glucose analyzer, a lancet, a blood collection needle and an analytical element, and combine them when necessary to perform the measurement. However, it takes a long time to train and it takes a considerable amount of time before a reliable measurement can be performed by the patient. Actually, measurements at sites other than the fingertip and forearm (abdominal wall, earlobe, etc.) are difficult even for a skilled person. In recent years, biosensors that can be measured with a sample volume of 1 μl or less have been developed due to the need for supplying less invasive specimens with less pain. The work of supplying accurately becomes very difficult. As a result, the measurement fails, and the patient who is the subject has the inconvenience of having to puncture again and replacing the biosensor and restart the measurement.
JP-A-9-266898 Japanese Patent Publication No. 8-20412

Thus, several needle-integrated biosensors have been devised. First, in the needle-integrated biosensor disclosed in Patent Document 3, the puncture needle and the biosensor are placed in different positions in a pen-type (two-color ballpoint pen-like) measuring device equipped with a puncture needle drive unit. The blood glucose is measured by placing the tip of the pen-like measuring device against the skin of the subject and puncturing it, exposing the biosensor to the tip, and collecting blood. However, in this method, the troublesomeness of setting the needle and the biosensor in the measuring device has not been solved.
JP 2000-217804 A

Moreover, in the needle-integrated biosensor disclosed in Patent Document 4, the puncture needle is entrusted to external driving, and the puncture needle moves in parallel along the longitudinal direction of the elongated piece-like biosensor. Have taken. However, in this type, since blood collection is sent to the entire space sharing the sample conveyance path and the puncture needle passage, blood collection is more than necessary. In addition, since the shape of the entire needle-integrated biosensor is bilaterally symmetric, the user may mistakenly insert the biosensor into a measuring device equipped with a puncture drive.
Republished 2002-056769

  Thus, in the conventional needle-integrated biosensor, since the electrode system is formed on the flat substrate, the structure is flat, and it is necessary to fill the flat surface with the sample liquid, resulting in a large sample volume. There was a problem of becoming.

  An object of the present invention is to provide a needle-integrated biosensor that can minimize the amount of blood collected after puncturing.

An object of the present invention is to provide a biosensor in which a conductor and a spacer constituting electrodes and terminals are provided in a space sandwiched between two electrically insulating substrates, and a subject placed in the biosensor. In a biosensor in which a puncture needle for piercing the skin and collecting body fluid is integrated with a puncture needle support, the puncture needle is formed of a rectangular conductor formed on each of two substrates. This is achieved by a needle-integrated biosensor that is positioned between opposing electrodes that are arranged opposite to each other in a manner perpendicular to the longitudinal direction .

The needle-integrated biosensor according to the present invention has a puncture needle positioned between facing electrodes arranged to face each other in a mode orthogonal to the longitudinal direction of a rectangular conductor formed on each of two substrates. Therefore, it has an excellent effect of enabling efficient measurement without collecting blood more than necessary after puncture. Moreover, when it is made into the left-right asymmetric shape centering on the puncture needle, the erroneous insertion to the measuring device at the time of use can also be prevented.

  As the substrate, it is sufficient if it is electrically insulating, for example, plastic, biodegradable material, paper or the like is used, and preferably polyethylene terephthalate is used.

  The electrode is formed on the substrate by a screen printing method, a vapor deposition method, a sputtering method, a foil pasting method, a plating method, etc., and the materials include carbon, silver, silver / silver chloride, platinum, gold, nickel, copper, Examples include palladium, titanium, iridium, lead, tin oxide, and platinum black. Here, as the carbon, carbon nanotubes, carbon microcoils, carbon nanohorns, fullerenes, dendrimers, or derivatives thereof can be used.

  The electrode may be a two-pole method formed with a working electrode and a counter electrode or a three-pole method formed with a working electrode and a counter electrode, a reference electrode, or an electrode method with more poles. Here, when the tripolar method is adopted, in addition to the electrochemical measurement of the measurement target substance, it is possible to measure the moving speed of the blood sample introduced into the transport path, thereby measuring the hematocrit value. Moreover, you may be comprised by 2 or more sets of electrode systems. These electrodes are formed separately on two substrates.

In other words, the electrodes are opposed to each other, specifically, an electrode forming part of a conductor formed on the surface of two substrates sandwiches a spacer made of a resist layer or an adhesive layer. Adopt a face-to-face structure. As a result, the electrochemical reaction proceeds efficiently, and the volume of the reaction layer can be effectively reduced by reducing the distance between the electrodes and the electrode area. As a result, the number of samples can be reduced.

  A reagent layer (electrode reaction part) can be formed on the substrate on which the electrode is formed. The reagent layer is formed by a screen printing method or a dispenser method, and the reagent layer can be immobilized on the electrode surface or the substrate surface by an adsorption method involving drying or a covalent bonding method. Examples of the reagent disposed in the electrode reaction part of the biosensor include those containing glucose oxidase as an oxidase and potassium ferricyanide as a mediator when configured for blood glucose measurement. When the reagent is dissolved by the blood, the enzyme reaction is started. As a result, potassium ferricyanide coexisting in the reaction layer is reduced and potassium ferrocyanide, which is a reduced electron carrier, is accumulated. The amount is proportional to the substrate concentration, ie the glucose concentration in the blood. The reduced electron carrier accumulated for a certain time is oxidized by an electrochemical reaction. An electronic circuit in the measurement apparatus main body, which will be described later, calculates and determines a glucose concentration (blood glucose level) from the anode current measured at this time, and displays it on a display unit arranged on the surface of the main body.

  In addition, a surfactant and lipid can be applied around the blood collection port and on the surface of the electrode or reagent layer (electrode reaction part). By applying a surfactant or lipid, the sample can be moved smoothly.

  Here, there is a possibility that the puncture needle contained in the inside of the sample conveyance path is contaminated by the application of the reagent layer, the surfactant or the lipid into the sample transport path. In order to prevent such contamination, it is preferable not to apply these reagents around the tip of the puncture needle.

  In the biosensor in which the reagent layer is provided on the electrode filled with the above blood collection, the blood collection and the reagent react when the blood collected from the blood collection port contacts the reagent layer on the electrode. This reaction is monitored as an electrical change at the electrode.

  Further, in the biosensor, the electrode may be defined by a resist layer, and this resist layer can be easily formed by screen printing or the like. The resist in this case is not particularly limited as long as it does not react or dissolve with the substrate, as in the case of the adhesive, and examples thereof include ultraviolet curable vinyl / acrylic resins, urethane acrylate resins, and polyester acrylate resins. Can be mentioned. The purpose of using the resist is mainly to clarify the electrode pattern and to clarify the above-mentioned definition of the electrode area, and to insulate the sample transport path where no reagent layer is present. Therefore, the resist layer may or may not form the same pattern as the adhesive layer. In the latter case, the resist layer is preferably formed on the electrode substrate for insulation. Furthermore, by providing this resist layer thicker than the electrode in the sample transport path in which the puncture needle of the needle-integrated biosensor of the present invention is accommodated, contact between the puncture needle and the electrode can be suppressed. Such a resist layer can also be formed by a screen printing method. For example, the resist layer formed with a thickness of about 5 to 500 μm, preferably about 10 to 100 μm, using any of the above-mentioned materials also acts as a spacer. To do.

  The two substrates are bonded via an adhesive such as an acrylic resin adhesive to constitute a biosensor. Such an adhesive layer can also be formed by a screen printing method, and is formed with a thickness of about 5 to 500 μm, preferably about 10 to 100 μm, and such an adhesive layer acts as a spacer as well as a resist layer. In addition, the said reagent can also be contained in an adhesive bond layer. The adhesive layer may be either the same pattern as the resist layer or a different pattern.

  In addition, a biosensor as a folded molded body can be manufactured by folding the substrate having the above-described configuration in which the puncture needle is disposed along the connecting portion. As the connecting portion, the length of the connecting portion is not less than the thickness of the spacer, that is, 0.5 to 4 mm, preferably 1.0 to 3.0 mm, and preferably at least two places are provided between two substrates. If such a connection part has a length of about 0.5 to 0.9 mm on the insulating substrate, for example, a gear-shaped thin disk whose convex part is a blade, a broken line shape In addition, a connecting portion having a length of about 1 to 4 mm is hinge-molded by punching an insulating substrate with a mold. Here, when the connecting portion has a length of about 1 to 4 mm, there is no need to prevent the warping by fixing the folded portion by thermocompression bonding or using a fixture. In the case of a biosensor that is such a folded molded body, a connecting portion as a folding line is provided so as to be horizontal in the long axis direction of a long substrate, and further, an electrode or the like is formed and then folded along the connecting portion. After that, a large number of biosensors can be manufactured at once by punching into the sensor shape. The needle-integrated biosensor manufactured by such a manufacturing method has very good reproducibility and has features that cannot be achieved by a conventional lamination method.

  For puncture needles for collecting body fluid from the skin of the subject, it is necessary to puncture the subject. A thin puncture needle is preferable. Specifically, a 21-33 gauge thing by Terumo company is used. The puncture needle may be a hollow needle or a rod-like needle as long as it can penetrate the subject's skin. Furthermore, since the puncture needle needs to be stored hygienically in the biosensor until it is used, a photocatalytic function effective for antibacterial and antiviral effects may be imparted to the needle tip surface. In that case, a film of titanium oxide or titanium dioxide is desirable.

In the biosensor, a puncture needle for puncturing the subject's skin and collecting body fluid is arranged. The puncture needle is disposed between the electrodes in a state orthogonal to the longitudinal direction of the rectangular conductor . With this arrangement , the amount of blood collected can be reduced as compared with the case where the puncture needle is arranged in parallel to the longitudinal direction of the rectangular conductor, and the measurement terminal is out of the puncture needle trajectory Since the shape of the biosensor integrated with a needle can be made asymmetrical with the puncture needle as the center line by being arranged at the position, it becomes a mark for the user and the insertion into the measuring device is wrong. In short, the measuring device can also be provided with a mechanism for specifying the position of the terminal of the needle-integrated biosensor of the present invention.

  The biosensor having the above-described configuration is made of a soft material such as silicone rubber, soft polyurethane, polyvinyl chloride, or polystyrene foam at the time of manufacture under conditions of negative pressure, preferably vacuum conditions, than the outside air. On the puncture drive side, the inside of the sensor can be constructed by using a stretchable material such as natural rubber between the two substrates constituting the biosensor and the puncture needle support. Is sealed in a negative pressure state, and in addition to capillary action, a suction means can be used in combination for movement of blood collection into the sample transport path after puncturing. At this time, immediately after the puncture, the puncture needle is further pulled in the direction opposite to the puncture direction, so that the stretchable material is stretched and the negative pressure inside can be further increased to suck the blood sample. By adopting such a configuration, blood can be collected smoothly. Here, when the puncture needle is disposed orthogonal to the electrode, the terminal can be removed from the trajectory of the puncture needle. The structure can be easily obtained. In addition, the soft material covering the puncture blood collection port has an effect of maintaining negative pressure and improving the adhesion between the skin of the subject and the puncture blood collection port.

  In the needle-integrated biosensor of the present invention, it is desirable that a series of operations of puncture, blood collection, and measurement be performed by a measurement device having a puncture drive. In this case, for example, it is desirable that the puncture drive has a mechanism in which the needle penetrates the soft material of the biosensor and breaks through the skin of the subject, and a mechanism that quickly returns to the original position immediately after the puncture.

  Furthermore, when the needle-integrated biosensor of the present invention includes a suction mechanism, the puncture drive system in the measurement device may be further improved in order to increase the suction force during blood collection. That is, by using a mechanism that returns the puncture needle to its original position immediately after puncture, the stretchable material is stretched by further pulling the puncture needle in the opposite direction to the puncture direction, and the internal negative pressure is further increased. Also good.

  As a measuring device for a needle-integrated biosensor, a measuring device that uses operability and durability to ensure repeatable and reliable measurement using a needle-integrated biosensor and is easy to carry is used. Insert the needle-integrated biosensor into the introduction part at the bottom so that the puncture needle support is facing upward, and the terminal of the biosensor is connected to the connector of the measuring device, so that measurement is possible. The preparation for the measurement is completed by pulling the trigger to give the puncture drive to the inside of the needle integrated biosensor, and then the puncture, blood collection, and measurement are automatically activated by pressing the puncture start button switch. A system that finally leads to measurement results is used.

  An example of the structural features of the measuring device will be described in more detail. In this measurement apparatus, the puncture needle drive unit and the measurement apparatus unit are integrated, and the puncture needle drive unit includes a trigger unit, a puncture start button unit, and a drive unit using an elastic body such as a spring. On the other hand, for the measuring device section, the sensor introduction section, the connector, the electrochemical measurement circuit, the memory section, the operation panel, the measurement section that measures the electrical values at the electrodes of the biosensor, and the display that displays the measurement values at the measurement section Further, a radio wave, for example, Bluetooth (registered trademark) can be mounted as a wireless means. With such a slide structure, since the puncture drive is received while the needle-integrated biosensor is securely held, the strength of the entire measuring apparatus can be increased. The measurement device can further include a mechanism that can recognize the left-right asymmetric structure with the puncture needle of the needle-integrated biosensor as the center line by the protruding portion of the measurement terminal.

  The puncture drive of the measuring device is preferably a mechanism that returns quickly after tapping the upper part of the needle-integrated biosensor in the vertical direction, and preferably has a mechanism that can adjust the depth at which the skin of the subject is punctured.

The measurement device must have voice guidance and voice recognition functions for visual impairment caused by diabetes, measurement data management function with built- in radio clock, communication function for medical data such as measurement data, and charging function. Can do.

  A measurement method in the measurement unit of the measurement apparatus is not particularly limited, and potential step chronoamperometry, coulometry, cyclic voltammetry, or the like can be used.

As described above, the needle-integrated biosensor of the present invention does not limit the user, that is, can handle a universal project.

  The needle-integrated biosensor according to the embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following examples unless it exceeds the gist.

FIG. 1 shows an assembly example of the needle-integrated biosensor of the present invention. FIGS. 1a) to c) are examples of manufacturing a needle-integrated biosensor, i) is a constituent material required for manufacturing the needle-integrated biosensor, and ii) and iii) indicate the molded body. FIG. 1a) shows a resist layer 6 in which rectangular conductors 7 constituting electrodes and terminals are formed on the surfaces of two plate members as biosensor substrates 1 and 1, respectively. The resist layer 6 serves not only as a spacer 2 but also to define the electrode area and to prevent contact between the electrode surface and the puncture needle. Accordingly, the through-hole 4 is provided in the resist 6 layer. Here, the board | substrate 1 can be safely used by rounding a corner | angular. FIG. 1b) shows how the adhesive layer 5 is formed on the resist layer. Here, since the adhesive layer 5 is also provided between the plate members of the substrates 1 and 1, like the resist layer 6, it plays the role of the spacer 2. Further, FIG. 1b) ii) shows an electrode 10 and its electrode reaction part 13 whose area is defined by the resist layer 6 and the adhesive layer 5. FIG. 1c) i) shows the configuration of the puncture needle section 14. The puncture needle section 14 is composed of a puncture needle 20, a support body 19 that supports the puncture needle 20, and an external drive connection section 17, and the external drive connection section 17 is shown. Is connected to a measuring device equipped with a puncture drive so that the puncture drive from the measurement device can be obtained. Further, FIG. 1c) shows that the puncture needle portion 14 is disposed on the electrodes 10 and 10 along the sample transport path 8 and perpendicular to the longitudinal direction of the rectangular conductor . As shown in this figure, the puncture needle portion 14 has a structure in which contact with the electrode surface 10 can be avoided by forming the resist layer 6. Therefore, even if the reagent layer 13 is formed on the surface of the electrode 10, contact between the reagent layer 13 and the puncture needle portion 14 can be prevented, and as a result, contamination of the puncture needle 20 with the reagent can be prevented. . FIG. 1c) iii) shows the needle-integrated biosensor 3 formed in this way.

FIG. 2 shows a cross-sectional view of the needle-integrated biosensor 3 shown in FIG. FIG. 2b) shows a cross-sectional view taken along the line AA 'shown in FIG. 2a). As shown in this figure, a puncture needle 14 is arranged on the pattern surface provided on the substrate 1 of the biosensor. FIG. 2c) shows a cross-sectional view along BB ″ shown in FIG. 2a). A puncture needle 14 is disposed at the center of the two substrates 1 and 1. As shown in these figures, the structure of the needle-integrated biosensor 3 of the present invention is such that the electrodes 10 formed on the inner sides of the two substrates 1 and 1 are attached so that they face each other. There is no. Furthermore, the long axis direction of the rectangular conductor 7, 7 puncture needle 14 is orthogonal, it is possible to remove the terminal 11 from the track of the puncture needle 14 by being placed on the electrode 10, 10. Further, since the terminal 11 is disposed at a position off the trajectory of the puncture needle 14, the shape of the needle-integrated biosensor 3 is asymmetrical with the puncture needle as the center line, which is a mark for the user. The insertion into the measuring device can be performed without mistake, and the measuring device can also be provided with a mechanism for specifying the position of the terminal 11 of the needle-integrated biosensor 3 of the present invention. Further, by reducing the width of the electrode and the distance between the electrodes, the width of the substrate at that portion is also reduced, so that the amount of the sample solution can be reduced.

  FIG. 3 shows an example of use of the needle-integrated biosensor 3 shown in FIGS. In FIG. 3, steps a) to d) are shown. In i) and ii), the state of the needle-integrated biosensor 3 at that time is shown in i) as a configuration diagram, and in ii) as shown in FIG. 'Shown in cross section. FIG. 3a) shows a state before use of the needle-integrated biosensor 3 connected to a measuring device with a puncture drive. At this time, the skin as the subject is in close contact with the puncture blood collection port 12 of the needle-integrated biosensor 3. FIG. 3b) shows the state of puncture, which is not shown, but the puncture needle 20 protrudes from the sensor and pierces the skin. FIG. 3c) shows a state where the puncture needle portion 14 has returned to its original position after puncturing. FIG. 3d) shows a state where the blood collection 24 from the punctured skin is subsequently sucked by capillary action.

FIG. 4 shows another configuration example of the needle-integrated biosensor of the present invention. 4a) to 4d) are examples of manufacturing a needle-integrated biosensor, i) is a constituent material required for manufacturing the needle-integrated biosensor, and ii) and iii) indicate the molded body. 1 differs from the needle-integrated biosensor shown in FIG. 1 in that a biosensor (folded molded body 18) can be assembled by providing a connecting portion such as a perforation on a single flat substrate. It is in the point to have. First, the biosensor assembled by such a folding method is characterized in that the manufacturing process can be simplified since the substrates do not need to be overlapped unlike the manufacturing method by the stacking method in the case of FIG. Therefore, it can be said that the method is suitable for mass-producing high-precision sensors with high yield. Further, the connecting portion 21 of the board necessary for the folding structure is also a hook 22 for fixing the elastic material 16 to the board 1 as shown in FIG. 4 d) ii). On the other hand, this blood collection / suction mechanism includes a sample transport path / puncture drive unit 8 by means of an elastic material 16 for sealing the space between the soft material 15 near the puncture blood collection port 12 and the substrate 1 and the puncture needle support 17. It is established by shutting off the outside air. Further, the soft material is also useful for bringing the skin of the subject into close contact with the puncture blood collection port 12.

FIG. 5 shows a cross-sectional view of the needle-integrated biosensor 3 shown in FIG. FIG. 5b) is a cross-sectional view taken along the line AA 'shown in FIG. 5a). As shown in this figure, a puncture needle 14 is arranged on the pattern surface provided on the substrate 1 of the biosensor. Further, the puncture needle portion 14 is fixed to the substrates 1, 1 and the bonding portion 23 by an elastic material 16. FIG. 5c) shows a cross-sectional view along BB ′ shown in FIG. 5a). A puncture needle 14 is disposed at the center of the substrates 1 and 1. As shown in these drawings, the structure of the needle-integrated biosensor 3 of the present invention is such that the rectangular conductors 7 and 7 are arranged on the electrodes 10 and 10 so as to be orthogonal to the puncture needle 14 so that the terminal 11 is provided. The puncture needle 14 can be removed from the trajectory, so that airtightness for keeping the inside of the sample transport path 8 including the puncture needle 14 at a negative pressure can be easily obtained. Further, by reducing the width and conductor spacing of the conductor, since also small width of the substrate of the part, it is a small amount of the sample liquid amount. Furthermore, since the terminal 11 is arranged at a position off the trajectory of the puncture needle 14, the shape of the needle-integrated biosensor 3 becomes asymmetrical with the puncture needle as the center line. Thus, the insertion into the measuring device can be carried out without mistake, and the measuring device can also be provided with a mechanism for specifying the position of the terminal 11 of the needle integrated biosensor 3 of the present invention.

  FIG. 6 shows an example of use of the needle-integrated biosensor 3 shown in FIGS. In FIG. 6, each step is shown by a) to d), i) and ii) show the state of the needle-integrated biosensor 3 at that time in i), and in ii) the A-A shown in FIG. 5a). 'Shown in cross section. FIG. 6a) shows a state before use of the needle-integrated biosensor 3 connected to a measuring device with a puncture drive. At this time, the skin as the subject is in close contact with the soft material 15 provided in the puncture blood sampling port 12 of the needle-integrated biosensor 3. FIG. 6 b) shows the state of puncture, and shows the state where the puncture needle 20 penetrates the soft material 15. Although not shown, the puncture needle 20 also pierces the skin at this time. Further, it can be seen that the elastic material 16 is contracted. FIG. 6c) shows a state where the puncture needle portion 14 has returned to its original position after puncturing. Here, the soft material 15 penetrated by the puncture needle 20 is shown. In this state, the negative pressure in the biosensor is applied to the punctured skin. FIG. 6d) shows a state in which the bleeding 24 from the punctured skin is subsequently sucked by the internal negative pressure.

It is a figure which shows one assembly example of the needle-integrated biosensor according to the present invention. It is a figure which shows one structural example of the needle-integrated biosensor according to the present invention. It is a figure which shows the usage example of the needle | hook integrated biosensor which concerns on this invention. It is a figure which shows the other assembly example of the needle | hook integrated biosensor which concerns on this invention. It is a figure which shows the other structural example of the needle | hook integrated biosensor which concerns on this invention. It is a figure which shows the other usage example of the needle | hook integrated biosensor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Spacer 3 Needle-integrated biosensor 4 Through hole 5 Adhesive layer 6 Resist layer 7 Conductor 8 Sample transport path / puncture needle path 10 Electrode 11 Terminal 12 Puncture blood sampling port 13 Electrode reaction part (reagent layer)
14 Puncture Needle 15 Soft Material 16 Stretchable Material 17 External Drive Connection 18 Folded Molded Body 19 Puncture Needle Support 20 Puncture Needle 21 Connection 22 Hook 23 Adhesion 24 Blood Collection

Claims (5)

A biosensor provided with conductors and spacers constituting electrodes and terminals in a space between two electrically insulating substrates, and a body fluid collected by piercing the skin of a subject placed in the biosensor In a biosensor configured to be integrated with a puncture needle through a puncture needle support,
A needle-integrated bio, wherein the puncture needle is located between facing electrodes arranged to face each other in a mode orthogonal to the longitudinal direction of the rectangular conductor formed on each of the two substrates sensor. The needle-integrated biosensor according to claim 1, wherein a reagent layer is provided on one or both of the electrode and its periphery . The needle-integrated biosensor according to claim 1, wherein the spacer is composed of one or both of a resist layer and an adhesive layer . Spacer is constituted by a resist layer or it and the adhesive layer, the needle-integrated biosensor of claim 1, wherein the resist layer is formed thicker than the electrode. The needle-integrated biosensor according to claim 1, wherein the biosensor has an asymmetrical shape with the puncture needle as a center line.

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