TW201209408A - Fully integrated micro biosensor - Google Patents

Abstract

There is provided a fully integrated micro biosensor. The invention uses the standard complementary metal oxide semiconductor biomedicine micro electro mechanical systems (CMOS Bio-MEMS) process to manufacture a biosensor embedded with a sensing circuit. The biosensor includes a fork shaped inter-digital electrode structure and an oscillation circuit. A self-assembling single-layer thin film technique is employed to modify the macromolecular compounds on the metal surface to form a self-assembled single-layer thin film. Then, a sensor device with a high unity for a specific substance is arranged on the self-assembled single-layer thin film. When detecting that the thin film absorbs the specific substance, the dielectric coefficient of the aforementioned electrode structure is changed and thus results a capacitance variation. The sensing circuit converts the capacitance variation into a frequency for output, so as to measure the concentration of the specific substance. In addition, the sensing circuit includes an oscillation circuit capable of adjusting the output frequency. The biosensor is integrated onto a portable carrier. The sensor device can be a glucose oxsidase (GOD), or one of the enzyme, antibody, antigen and antibiotics attached with lipopolysaccharide (LPS).

Description

201209408 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to biological _|| money, more specifically, a micro-integrated biosensor including a circuit, particularly glucose micro-sensing Device. [Prior Art] Biosensors are defined as "using immobilized biomolecules (lmmobilized bi〇m〇lecules) in combination with transducers to detect environmental chemicals in the body or in vitro, and Ludang substances. A device that reads a generated signal and responds after a specific interaction with a biomolecule. In the current clinical tests, the samples to be tested contain a variety of substances. If a certain factor (4) is to be measured, it is necessary to detect the signal reaction of a specific substance by a highly scale-sex reaction, so the biosensor is Use this advantage to develop. The biosensing H is the classification of the biological differentiation silk. The ugly part of the towel consists of two components, the biosensor signal receiving or generating a part, such as a molecular element from a biological molecule, a tissue part, or a clock cell. Another—for the _ letter _ replacement component, belongs to the hardware _ device component. Therefore, the biosensor is basically composed of three different units: (1) biometric components; (2) sensors; and (3) signal processors. Therefore, how to combine specific bioactive molecules (bi〇丨〇gjca| materials) that have been separated, purified or synthesized by biochemical methods can be accurately combined with fast-reacting physical transducers to form a set of organisms. Sensor Response System' This is the main purpose of studying biosensors. In 1962, Clark and Lyon first developed an enzyme electrode as a biosensor. [Note U's use of current-based sensing technology to detect glucose concentration, the principle is to electrochemically measure the product on a specific electrode. The amount of production or the amount of reactant consumed. 201209408 [li 1: LC Clark, Jr., C. Lyons, Electrode System for Continuous Monitoring in Cardiovascular Surgery, Ann. NY Acad. Sci., v〇I. 148, pp. 133-135, 1962.] 2002 Gao Et al., proposed an array of integrated biosensors [Note 2] containing oxygen and glucose sensing H for detecting blood metabolism parameters of the human body. Local oxygen concentration and (iv) sugar concentration can be detected in less than - minutes. In the thin ride, (four) hetero-half permeable membrane and oxygen semi-permeable membrane, when glucose passes through the glucose semi-permeable membrane, hydrogen peroxide is generated immediately, and then oxygen is sensed by n-sensing hydrogen peroxide to know the oxygen content, indirect amount Measure the amount of impurities. In design

The considerations for the consideration are film material, film thickness, solid electrolyte layer, and electrode area. The sensor's read signal uses current as the sensing mechanism. [Note 2: C. Gao, Jin-WooChoi, M. Dutta, S. Chilukuru, J. H Nevin τ v τ MG Bissell, CH Ahn, MA fully integrated biosensor arrav for m . ee' of metabolic parameters in human blood, 11 Microtechnol〇gies in Biology 2nd Annual International IEEE-EMB Special T〇pic Conference, pp"223-226 2004 0〇e et al.' proposed an ET type enzyme biosensor [Note 3]. Using the gold electrode as the channel's _(Gate)t as the sensing surface, and then using the self-assembled single-layer film technology to make the surface modification of the gold electrode, it is connected with the gold electrode through the threat reading. The measurement sample _ whole blood and recorded two kinds of measurement, when the _ sample is whole blood, the sensitivity is 61.4 V / Onol / L), the sample is called blood, the sensitivity is m 2 V / (mol /L).

[l±3: K. 0〇e, Y. Hamaraoto, T. Kadokawa, T. Iuchi, Y Hirann U

BioMEMSanOanoi^ In 2005, Zhang et al. first cultivated a three-dimensional network on the gold surface and then modified the Jinnai to the colloid [Note 4]. After the combination of cystamine and glucose oxidase, as a sensing element, the sensing element and the Chennai green seed were twice surface-modified to complete the modification process of the entire 201209408 sugar sensor. Cyclic voltammetry (cv) and electrochemical impedance spectroscopy (EIS) were then used for electron transfer analysis and electrode surface impedance analysis. The sensor has a concentration detection limit of 23 mM, and has good repeatability and is stable for more than 60 days. [β主4^S·张,·N. Wang, Y. Niu, C. Sun, “Immobilization of glucose oxidase go nanoparticles modified Au electrode for the construction of biosensor," Sensors and Actuators B: Chemical, vol. 109 , Issue 2, pp. 367-374, 2005.] In 2007, Macaya et al. used conductive polymer PED〇T:pss as a channel for transistors, and platinum as a gate electrode to develop a simple sense of glucose. The detector [Note 5] has the sensitivity of micro-mole. When the gate is applied 〇. 6 V, the limit glucose concentration can reach 3 mM, and the sensor's human saliva is within the measurement range of gold sugar. There is a good response, and the sensitivity and sensing concentration range can also be detected by changing the gate voltage. The read signal of this sensor is current using the sensing mechanism. S5: [DJMa5aya, M .Nikolou, S. Takamatsu, JTMabeck, RHOwens, GG Malliaras, Simple glucose sensors with micromolar sensitivity based on organic electrochemical transistors, " Sensors and Actuators B: Chemical, vol. 123, Issue 1, pp. 374-378, 2007.] 20 In 2007, Li荨 [Note 6], ii-mercapt〇undecanoic acid (11-MUA) was surface-modified on the gold nanoparticles using self-assembled monolayer film technology, and then using the active agent EDC/NHS 11- The terminal functional carboxyl group of MUA is activated, and glucose oxidase is made into a G〇D/AuNPs sensing membrane to produce an enhanced thermal stability biosensor. [.£6 . D. Li, Q. He , Y. Cui, L. Duan, J. Li, Immobilization of glucose oxidase onto gold nanoparticles with enhanced thermostability, " Biochemical and Biophysical Research Communications, vol. 355, Issue 2, pp. 488-493, 2007.] 2008 Liu et al. [7] applied a conductive polymer (PED0T-PSS) as an organic film to immobilize glucose oxidase (GOD) on the gate channel of the transistor, while glucose oxidase utilizes a simple spin coating technique. It is fixed on the film, and then a driving voltage is applied to measure the gate current of the transistor. In terms of sensitivity, the concentration of glucose per 1 mM is 1.65, while the concentration of 201209408 is optimal from 1.1 mM to 16.5 mM, and the reaction time is between ι and 2 〇. The read signal of this sensor uses current as the sensing mechanism. [Note 7: J. Liu, M. Agarwal, K. Varahramyan, "Glucose sensor based on organic thin film transistor using glucose oxidase and conducting polymer," Sensors and Actuators B: Chemical, vol. 135, Issue 1, pp. 195 -199, 2008.] In 2009, Gopalan et al. [Note 8] used a new organic and inorganic hybrid nanocomposite to load glucose oxidase, the biosensor's sensing membrane.

The size of Nafion-silica/MWCNT-g-PANI is about 250 nm-1 egg, which is measured by electrochemical reaction to measure the change of current. When the glucose concentration is M0, it can show good linearity. The response has a sensitivity of 5. 01 raA/mM, a low response time (about 6 seconds), a reproducibility of 2.2%, and a long stabilization time. [Note 8: Α· I. Gopalan, KP Lee, D. Ragupathy, SH Lee, JW Lee, “An electrochemical glucose biosensor exploiting a polyaniline grafted multiwalled carbon nanotube/perfluorosulfonate ionomer-silica nanocomposite, M Biomaterials, vol. 30, Issue 30, pp 5999-6005, 2009.] ' The above literature discusses the current development of glucose sensors, most of which are divided into current and voltage measurements. The electrochemical measurement method is used to determine the glucose concentration and explore the film. The relationship between voltage and concentration is evaluated by electron transfer, film surface impedance, linearity and slope with glucose oxidase. The relationship between current and concentration is discussed by applying different films to the gate of the transistor. To do immobilized enzymes, and apply a gate voltage to measure the channel current, such as FET-type sensors. In the choice of film, because of the variety of polymers, and the adsorption of metal based on different polymers The materials are also different. The following literature will introduce the adsorption between gold and thiol molecules. 1992 Dubois et al. The characteristics of the film formed with sulfur [Note 9]. The paper indicates that the gold surface has low chemical activity, which is not easy to react with gas molecules in the air. When the self-assembled single layer 201209408 film is used, it is easy to form gold with sulfur as the head group. Chemical adsorption, and the operating environment is also easy to control, so the 竣 chain structure on sulfur can be connected to gold. [Note 9: LH Dubois, RG Nuzzo "ςνη+h. . · cv +

Organic Surfaces, ', Annu Rev Phvs rh 1S, j"uc ^re> and Properties of Model • Pnys. Chem, vol. 43, pp. 437-463, 1992.] Takao et al., 1998, explored self-assembly The effect of the time of the monolayer on the surface of the thiol molecule on the gold surface [Note 10]. In this paper, it is pointed out that the thiol molecule is modified on gold, and the high-resolution photoelectron spectroscopy is used to scan the sulfur 2p trace. The results show that if the self-secret single-layer film is repaired, the kidney bean will have no key on the gold. a thiol molecule, so a self-assembled monolayer film

It takes more than 24 hours to avoid this situation.

Wolfgang, ^ighVesolutio^ay phot^ Satoshl1 Ν· Naoki- S. Hiroyuki, K. octadecanethiol self-awpmhi ri 7 P, handsome eCtr〇n SPeCtr〇scopy measurements of 8^Γ2M6 19ΓΓ La^Uir> V〇L 14> In the above document, because the long-chain thiol molecule and the rhythm of the metal surface are combined with the formation of the outer layer of the sulphur element and the gold-based sub-domain, the stable thiol There are tight sides in the system of numerator-financial and gold atoms. It can be found from the literature that a lion molecule with a longer carbon chain has a lower _ ringing factor and a modification time of more than 24 hours to form a dense monomolecular film. SUMMARY OF THE INVENTION A blood glucose sensor is the earliest developed and commercialized biosensor. However, in view of the fact that the blood glucose is commercially available or the test is sewed, and the electrochemical technology needs to be coupled - the external circuit is not integrated in the sense circuit and the biosensor. It has the problems of large volume, inconvenient operation, unfavorable carrying, and difficulty in combining with the reduced objects. This case uses the standard biomedical micro-electromechanical process (CM〇s Bi〇_MEMS) technology to integrate a sensing circuit to make - miniaturized (four) sugar bio-lang II n points in the m system (sensing unit 201209408 == integer In addition to the advantages of ♦, the cost can also be reduced by means of mass production, and the whole vector can be reduced. (Example: mobile phones, watches, hats, etc. can be carried on long-term items. , go out and get out of the body «), the lake read _ push, you can transfer the filament to prevent emergencies" ^

And _ 彳曙 standard biology _ machine lion ((10) s national process, making a sense of early reading, the road is integrated into the body _ hiding micro sense. The sensing unit is set between the electrodes of the electrode structure - sensing End, the self-assembled monolayer film is modified on the sensing end, and the sensing element having a high degree of mono-sex is applied to the film, because the glucose oxidase and the lysine have a high degree of specificity. Moreover, lysine oxidase absorbs _glucose, which changes the dielectric strength between the electrodes of the interdigitated electrode structure and causes f-capacitance change. Designing a circuit to convert the capacitance change into a frequency output, thereby measuring different concentrations of glucose. The area of the glucose micro-sensor is 1.561x1.82 mm2. Because the bio-signal signal is a small signal change, the area of the sensing area is designed to be 43-face 2, and the large-area sensing area is used to enhance the signal change.

The circuit has a large output signal. According to the experimental results, when the glucose concentration is increased from _ to 10 mM, the output frequency measured by the spectrum analyzer will increase from 1〇4〇2MHz to 23.715MHz, and the sensitivity of the sensor is about. At 3 MHz/mM, this glucose biosensor exhibits good sensing performance. [Embodiment] For the convenience of the description, the central idea expressed in the above description of the invention is expressed by a specific embodiment. Various items in the embodiments are depicted in terms of ratios, dimensions, amounts of deformation, or displacements that are suitable for illustration, and are not drawn to the proportions of actual elements, as set forth in the foregoing. In the following 201209408 description, similar components are denoted by the same reference numerals. As shown in the first figure, the glucose biosensor of the present invention mainly comprises: a sensing unit 1', a sensing circuit 30 coupled to the sensing unit 10, and a signal output unit 40 coupled to the sensing circuit 30; The sensing unit 1 , the sensing circuit 30 , and the signal output unit 4 are mounted on a miniature substrate 50 , and thus the sensor is in a microchip type. The method for manufacturing the sensing unit 10 includes the steps from the second figure to the seventh figure: The sensing unit 10 of the present case is a capacitive electrode structure, and since the reaction signal to the living body is considered to be small, the structure is The design consists of a large capacitance value structure composed of the finger-shaped electrodes, which increases the sensing area and reduces the electrode spacing. In the design, the first to fourth metal layers 1Ί, 12, 13, 14 in the 0 35 CM〇s Bi〇MEMs process are the sensing electrodes, and the surfaces of the first metal layer 11 are sequentially arranged between the two electrodes. - Chromium layer 15 and - gold layer 16 serve as sensing regions. In order to increase the area of the sensing, in the design criteria of the selection process, the minimum allowable width of gold (4) is used as the distance between the two electrodes. By using (2.1), the capacitor is expressed as:

- χ) d~~ 2n^〇er *....................(2.1) where C is the capacitance value and η is the number of the electrode group 1 The vacuum dielectric constant, the value of which is 8.84χΐ〇12, (the dielectric layer dielectric constant 'is the electrode thickness, /_ is the electrode length, and the χ is the distance between the two parallel electrodes in different directions. Using the design of (2.1) The size of the measuring structure refers to the length of the re-shaped electrode is a (8) (four), the degree is 5 Mm, the spacing between the two electrodes is 14 (four), the number of electrodes is 6 〇, and the specification list is not. Because of the material of the metal layers 11 to 14 Yes, the gold is _ poor adhesion, so first on the ^ 201209408 genus layer is plated with gold chrome (c "), the new layer on the 1S layer - gold layer 16 ' and the thickness of the gold layer is 3000 A ' is used as the sensing end of the biosensor. 201209408 In order to simulate the f-value of the structure 'this article _ AnSQftQ3D Εχ 「 _ "6 software to simulate the capacitance loss of a single set of fingers f-pole" simulation results The single set of electrodes is about Q fine 817 ρρ, and is designed to refer to the number of forked electrode groups η * 6 〇, group, so multiplying a single set of electrodes by η is about 3.04902 ' is the sensed structure capacitance value. Preventing response signals is too low, the design] porphyrin electrical sensing structure in parallel with the valley 'start value of the capacitance 4 Q49Q2 pF.

The sensing unit 10 is fabricated by a 0.35 CMOS Bio-MEMS process in which a metal layer is used.

The inscription, chrome, and gold substrate layers are polycrystalline ♦ and are oxidized at each layer for isolation. If it is necessary to connect the metal layers to form a conduction, it is necessary to add a layer of a conductive layer made of a tungsten material. The _-shaped electrode structure used in this paper is composed of a metal alone and an oxide layer, which is covered with a wide 2 oxide layer to achieve insulation between the electrode and the electrode, so that an electrode is formed between the electrode and the upper and lower electrode plates. As a capacitive finger-like structure. The cross-sectional view of the sensing unit 1'' is as shown in the third figure' in the sense sheet having the layer of the photoresist layer 17, and the region between the electrode and the electrode. Since the surface modification of gold is required, the protective layer has been removed, but the circuit and the electrode in the cross-sectional view retain the protective layer as shown in the fourth figure. Remove the photoresist layer, the second method 201209408 疋 的 / / X bubble in acetone for about 15 minutes, so that the photoresist layer π on the surface of the wafer is dissolved in the propyl solution after the face wash, that is, the profile is as follows The four figures are shown.

The fifth, sixth, and seventh figures, using the self-assembled single-layer film technology (10) asse_ed monolayeri SAM) to mark the high-grade 琉 十 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 21 modified on the surface of the gold layer 16 ' The (4) chemistry enzyme technology allows (4) ua tail end of several groups (_C〇〇H) adsorption sensing element (4) glucose oxidase (9丨嶋e〇XSidase, GOD)22. Because glucose oxysuccinic acid has a high degree of specificity, #test sample (human _ blood or urine) is exposed to the above-mentioned _ unit family, «glucooxidase will automatically absorb the glucose 23 adsorption will change when it occurs Refers to the dielectric coefficient between the electrodes and causes a change in capacitance. The self-assembled monolayer film is a kind of highly ordered film formed by the chemical adsorption and self-organized Weihua long bond organic molecules spontaneously adsorbed on the surface of the appropriate body, because the surface of the substrate can be made to function. The purpose of the transformation of the 6-handed bio-sensing field has been used in the surface modification technology. The age of the scales · (a) section? The thickness of the layer varies with Μ; (2) the bond between the monolayer and the substrate is chemical _; (3) the unidirectional side of the monolayer has directionality; (4) the surface of the substrate depends on the needs of different materials, and the lake can be _ There are (iv) functional groups to be functionalized. Table 2 lists the different compounds that can be adsorbed on different substrates. 201209408 Table 2 Surface compound substrates that can be adsorbed on the substrate by different compounds - Organic decane compounds, Dioxide, Dioxide, Glass alkyl mercaptan, Gold-silver steel, Surface dialkyl sulfide gold - Alcohols and amines The acid silver, steel, and self-assembled monolayer film can be divided into three parts, as shown in the eighth figure: the first part 61 is a head group capable of chemically reacting with the surface of the gold layer 16, mainly utilizing A certain chemical bond between the molecule and the substrate is firmly adsorbed on the surface of the gold layer 16, and an organic thiol adsorbs on the gold surface to form an Au-S polar co-mussel bond. The second part 62 is a long carbon chain, and there is a weak varnish force between the chain and the chain. The weak force can stabilize the arrangement of the molecules in the thin raft, but must first When the molecules are adsorbed onto the surface of the substrate, the molecular structure between the molecular bonds will be shaped by the interaction between the molecular bonds. The third portion 63 is the official end of the molecule. When the molecular self-assembly forms a lag on the surface of the substrate, this portion is the property of the surface. So when we replace the terminal functional groups of the molecule, we can change the properties of the original substrate surface. If the _chemical reaction is converted to other reactive functional groups, the molecules of the second or even third layer can be adsorbed. S] In addition to trying to maintain its activity, the biological enzymes should be kept as close as possible to the surface of the transducer, and the stability of the molecules of the molecules will make the signal more obvious. As shown in the ninth figure, the first layer 64 is a surface material using a self-assembled single-layer thin Lai gold, using a polymer ^_ combined with gold; the second layer 65_the method of derivatizing the enzyme, 彳_saccharide oxidase" 1 [MUA 峨 咖 咖 „ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The dielectric constant changes the size of the capacitor. Therefore, in the sensing circuit designed next, the capacitance of the sensing structure changes, which causes the output frequency to change. Regarding the design and fabrication of the sensing circuit, the CM〇S isolating circuit is used as the main structure as shown in the tenth figure. The CMOS oscillator circuit consists of three inverters (|nverte"] '2, 3), resistors and capacitors'. Adding a voltage between the inverter and the inverter _ capacitor can control the output of the frequency. The output 〇 is connected to the ln her r 3 output connected to form a differential_circuit' so the intersection of 〇 and R, its waveform is transiently represented by a typical differential waveform, and the tenth-graph is the C-scale. The charging and discharging waveform of the differential circuit. When the voltage of w is greater than the voltage source bias or greater than the grounding point 贞 voltage, ^(four) age is pinned by the M〇s of the blessing. At this time, the periodic current will flow. However, the current flowing at other times is a very small leakage 々 "and although the value passes \/rw and the input voltage reaches the third inverter, it will start to change, K will also enhance _ action and change direction" That is to say - provide positive feedback. This will further improve the stability and predictability of the circuit. The waveform at point A is for the voltage of M〇s forward voltage (匕) and ^ The period of the shearing period is [and the sum of & as shown in Figure 12. And the differential circuit of the differential circuit of c Available K represents the formula (2.2):

Vr = VRe~T'IRC ^ · * * · ................ ?-) Calculate D1 and use equation (2.4): VTH-(VDD+VTH)eT^ c................................................. .................. = -RC ln(--λ V〇o^VTH} .................. .................................................. ...

[S] 13 201209408 For the same calculation, use 2 (2.5): T2 = -RC 1η(

V

DD V. ΤΗ 2Vdd~ V. ................................................. ... ΤΗ Because the threshold voltage \ΖΤΗ is about ^ \/DD (the error is not as large as α5'), the oscillation period Τ is expressed as (2.6): (2.6) Γ = Γ1+Γ2 =-/? C(ln-ii-+lnl^l 1 + 0.5 2 — 0,5 The output waveform at the % end of the CMOS RC oscillator circuit, as shown in Figure 13, can be seen

The output waveform is - branch. The Lanco_crushing circuit deduces the formula (2 7), as shown below: 2R'C( 0.405R7 V+^Γ + 0.693) (2.7) Express the equation (2.7) as another form, ie (2 8): / --1—~_ 2C(0.405/?e9 ................................ ............................(2·8)here

d =_ίΛ_ Since the resistance and capacitance of the recording circuit change the output frequency, when the ruler 7 and /3⁄4 in the ninth figure (4) are under three conditions, the frequency can be expressed as equation (2.9)-form (2 11): 0.559

If 7?/=7?_?= and /= .................................... ... /O QN 0.455 If and 2> ' /s ................................. ........ η 0.722 If]?2<<仏'RC .............................. .................................... (2.11) Finally, the designed ❹m road is like a trait Show that the county's RC subtraction circuit adds two inverters 'fourth and fifth inverters for the snubber circuit design, using MC) S switch [S3 14 201209408 change to change the delay time and adjust the frequency output size. A grounded capacitor is connected to the voltage source to provide a stable voltage source to prevent AC signal disturbance. The fifteenth figure is the oscillation circuit (4) configuration®. Capacitance is - reference electrical hybrid, Cs_ domain is the meaning of the finger-like structure, using cre々c_r parallel is to improve the signal resolution and better signal-to-noise ratio. The circuit simulation soft H HSPICE simulates the frequency output of the RC oscillator circuit and the relationship between capacitance and frequency. Table 3 shows the analog specification list parameters of the RC oscillator circuit. The input voltage source is set to 3.3 V, and the sixteenth 圊 is the analog oscillator circuit output waveform. In the (4) simulation environment, Lu substitutes the capacitance value from 3 PF to 50 pF into the HSPICE towel to simulate the frequency output change and observe the linearity of the frequency change, as shown in Figure 17. When the capacitor rises from 3 pF to 5 〇 ^, the frequency drops from 103_11 MHz to 8.13 MHz. Table 3 oscillator circuit specifications

The required i-ride, the commutating liquid (V) are 2〇mbu 15 201209408 where Μ is the volume of the molar concentration, " is the solute molar number, ^ is the solution per liter, w is the solute weight, Quzhou is the solute molecular weight. Table 4 shows the weight of glucose required for the concentration of glucose from j yang |^ to 1 〇(71)^. Table 4 Glucose grams required for concentration 1~1〇 mM

First, the first part is carried out, and the unmodified glucose oxidase wafer is measured, and the wafer is measured to complete the self-organized material thin surface, and the surface is tilted on the gold surface (10). When the wafer is not subjected to a self-assembled monolayer film, no chemical molecules are attached to the gold surface at this time, so the dielectric layer between the interdigitated electrodes can be regarded as air, and the dielectric constant (10) of the air is 彳. The measured frequency of the wafer is 71.4 MHz; after the (4) UA is modified to the surface of the gold layer, because there is a polymer 11_MUA between the fingers and the electrode, the dielectric constant is increased by liter, according to (2, when dielectric In the case of liters, the capacitance value c will rise, and (2, because the fresh content c is inversely proportional', so the capacitance C rises and the frequency draws down. The wafer is finished with the measured output (5) 201209408 The frequency is 69.94 MHz , which is 1.46 MHz lower than the unmodified 71.4MHz, indicating that the dielectric between the fork electrodes has changed, and 11-MUA successfully combines with the gold surface. The glucose concentration of 1 mM is dispensed onto the sensing wafer. The upper finger-like structure area, and then repeatedly press the spectrum analyzer's modulation control red to scan the highest frequency of the wafer, the highest output frequency is 10.167 MHz. Because the functional group of 11-MUA is carboxyl group, the molecular formula c〇〇H While glucose is readily soluble in water and in water The towel is prone to hydrogen bonding. The sugar and the county will combine with the van der Waals force. So after the glucose concentration of 1 mM is measured, the wafer is immersed in ethanol and lightly stirred for a few minutes, and then heated at a low temperature. The temperature is about 4 CTC, and the ethanol is removed by evaporation, and the glucose concentration of 2 mM is measured. The measurement step of glucose concentration of 2 mM is the same as the concentration of mM, and the measured output frequency is 10.238 MHz. With an output of 1 mM, the frequency of the fresh sputum increased by 0.071 MHz. 'Because the dielectric constant of pure water is about 80, when the other substances are added, the dielectric coefficient is lowered. 'When the concentration of glucose is higher, it is because of the Waldorf force. The absorbed glucose will increase, so that the dielectric constant is decreased. When the dielectric constant is lower, the lower the capacitance c, the higher the output frequency, and the higher the output, the lower the concentration of 2 mM glucose. The frequency ratio is _high. The wafer is subsequently measured for different glucose concentrations, and the measured concentrations are 3 _, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM ' 1Q _ The output frequency is 10.386 MHz, 10.527 MHz '1〇·622ΜΗζ, 10.778 MHz, 10.935 MHz, 11.131 MHz, 11.366 MHz, 11.570 MHz. The correspondence between concentration and output frequency is plotted as shown in Figure 18, when the glucose concentration increases from ! mM to 1〇 At mM, its output frequency rises from 10.238 MHz to 11.570 MHz, and its curve rises linearly, while the total variation of the round-out frequency is 1403 MHz, and the sensitivity of the sensed wafer is about 〇14. [S3 17 201209408 2nd:: The second part of the amount; Cong (four) glucose oxidase wafer, measuring the modification of the sensory of dioxetane, the rate is after the coffee, and then repair the paste ___. ^4==ua rises, thunder μι Γ rises *" electric coefficient heart, liter, and by (2.8), it can be seen that when the capacitance 〇 rises, the frequency corpse falls, and the gamma _ decoration will be adjusted to a good concentration. The 彳__stack is overlaid on the 指(五) strong interdigitated structure area, and then with the aforementioned repeated-like measurement step, the measured output frequency of the sensing wafer is 10.402 MHz. Because glucose oxidase and (iv) UA are bound by covalent bonds, after the measurement is completed, _ethanol removes lysine and does not (4) wash the oxidase. After the cleaning is completed, the sample is heated by the seam temperature, and the crystal β is used for the glucose measurement with a concentration of 2 _ to 1 〇 _. Subsequent glucose concentrations from 2 mM, 3 mM, 4 mM, 5 _, 6 mM, 7 mM, 8 mM, 9 mM, and 10 _, with an output frequency of 13 〇7〇_, 14 316 MHz, then 〇9 MHz, 17.270 MHz, 18_638 MHz 19.834 MHz, 20.955 MHz, 22.312 MHz, 23.715 MHz. The concentration of 1 mM to 1Q _ and its corresponding output are freshly arranged as shown in Figure 19. When the glucose concentration increases from 1 mM to 10 mM, the output frequency increases from 1〇4〇2 MHz to 23.715 MHz. The linear change in 'the total change in output frequency is 彳3 3彳3 mhz, while the sensitivity of the sensed wafer is about 1.313 MHz/mM. I S1 18 201209408

When the sensing area in the middle of the finger-shaped electrode in the sensing wafer is modified after u-mua and 11_MUA/glucose oxidase, the glucose solution is dripped, and the pure water content of the dielectric layer is caused by 11-MUA. Less, so the dielectric coefficient will be lower than pure water, and after the modification of the glucose oxidase between the two electrodes, the dielectric coefficient is further reduced, so the sensing wafer has modified glucose emulsified enzyme, tb does not modify the ruthenium oxidation. The enzyme, which is measured by the thorns, is higher. This silk can be compared with the 18th and 19th, and confirmed by the twentieth. Because glucose oxidase has a high degree of specificity for binding to (4) sugar, when the sensor wafer is modified with glucose oxidase, the glucose oxidase is tightly bound to glucose, causing the dielectric coefficient & change between the fingers. More obvious 'so the output frequency signal of the chip is also more obvious. When the sensing wafer has only modified 11-MUA, its glucose concentration is from _ to 1 〇 _, the measured output fresh change is 彳.MHz, and the modified (d) is used with the glucosinol sensing wafer. The change in the output frequency is 13313 mHz. It can be seen that the sensing wafer with _ glucose oxidase has a large signal_degree. ^ ★ The sensing area of the sensing chip itself is designed to be large, so it can be seen from the twentieth picture that the higher the glucose concentration is, the larger the difference in output frequency will be; the sensing area has Portuguese檐 檐 酵 , , , , , , , , , , , , , , , , , , , , , , , , , , Therefore, in the case of the amount of Wei is 彳__, whether Lin has a "sugar oxidase, the frequency of the detection of the wafer is low" and the output frequency after modification of glucose oxidation is less obvious. The concentration of the shouting is measured from 1_(four)_ for ten rounds of freshness measurement, and the measurement is shown in Table 5. The formula of the fine standard deviation is used to calculate the standard deviation of the output frequency of the sugar concentration from 彳_ to 10 201209408, and the average value and standard deviation of each concentration are shown in Table 6. Table 5 The output frequency of glucose concentration to

Number of times 1 2 3 ----- 4 5 6 7 8 9 10 ImM 10.582 10.426 10.434 10.214 10.371 10.355 10.394 10.465 ΪΟ 4S7 10,504 13 091 2mM 13.06 13.044 13.099 13.139 13.021 [13.052 13.013 13.091 ΐΓ〇52 a 3 mM 14.024 14.51 14.15 14.346 14.189 14.612 14.44 14385 14.252 14 362 4 mM 16.377 16.554 16.149 16.776 16.4 16.023 15.71 15.616 16.518 1A zi'yo 5 mM Π.654 17.09 a 17.788 17.387 17.725 17.85 17.826 17.772 17.764 Π 6mM 18.274 18.133 18.25 18.367 18.202 18.814 18.556 18.399 18.375 18 484 7 mM 19.949 20.542 20.077 19.774 19.818 19.647 19.671 ]9.647 19.631 19 61] 8 mM 21.13 21.235 _ 21.555 ------ 21.334 21.154 21.242 20.941 20.909 20.901 21.031 9mM 10 mM 22.056 23.178 2].817_ 23.415 _ 22.065 ----- - 23.244 22.064 23.312 22.141 2Ϊΐ'ΐΤ~ 22.937 23.285 22.988 23.269 22.971 23.156 22.088 23.066 22.131 23.007 'The results are shown in the second ~f-• figure. 'The standard error is large; the concentration is 5. The standard deviation calculated in Table 6 is indicated in the curve. It is observed that the standard error is slightly lower at mlVI mM and 8 _ at glucose concentrations of 4 mM and 9 mM. In other indifferent conditions, the standard error is not the same. The enzyme feeling of the development of the secret case is mainly measured by the reaction of the sugar and (four) glycolysin IS1 20 201209408, and the two of them are touched. It is called fine coffee, and it is relatively fixed. On the surface of the gold layer, the probability of reaction between oxidized enzyme and _ sugar is also relatively high. The error on the measuring instrument also needs to be sealed' so that this is also the reason why the standard error caused by the result of the twentieth-figure: after the second-degree measurement is repeated. / Twenty-second picture is "change in the sense of glucose concentration (four), the measurement method is to use the three-meter to observe the voltage change of the drip glucose _, before the voltage value is determined, after the voltage is stable Drip the glucose onto the sensor, press the timer at the same time, and observe the change of the voltage value.

After the radiance is stabilized, the time at which the wafer senses glucose can be measured. From the time change in the figure, it can be observed that the time of sensing the crystal (4) sugar can be completed in 3 minutes. Because the reaction of glucose touch m is based on the collision probability, it causes different concentrations in time and measurement. The measurement time required is also different. In this case, a glucose biosensor was fabricated using a CMOS standard process, and the surface modification was performed by a self-assembled single-layer film technique. Due to the sulfur deposition of the polymer AMUA, "the gold has a spontaneous adsorption characteristic of chemical bonding, and the 11-MUA can be combined with the wafer, and the glucose oxidizing material (GO_ is set as a fine element on the wire φ) through the u_MUA. (4) Between the sugar oxidase and glucose, a biosensor is developed because of the specific adsorption characteristics. The oscillating circuit is integrated into the sensing chip as a signal conversion sensing circuit and utilized. The capacitance-to-frequency output conversion of the oscillating circuit senses different concentrations of glucose. When the driving voltage is 3.3 V, the surface-modified wafer has an operating frequency of 65.79 MHz; when the equivalent glucose concentration is 1 ηιΜ, The output frequency is 10.402 MHz; when the concentration is raised to 10 mM, its output frequency is 23.715 MHz, its frequency changes by 13.313 MHz, and the average output changes by 1 (7)^. The output frequency changes by about 1 33 MHz, which can then be applied to the sensor. The sensing area is adjusted. 21 201209408 The effect of W姨 rate is increased. For example, the sensing area and the circuit should be avoided too close, and the parasitic capacitance is reduced. Measuring area, so that the sensing component can be stably adsorbed and amplified. At present, the sensing chip with wireless transmission function has been widely used in life, and the CMOS process and circuit are integrated in the life. In the future, the RF component can be added to make the sensing chip have wireless transmission function. 'As long as the sensor can convert the output signal of the circuit into an RF signal, the external RF system can be used to achieve the wireless transmission function. The bio-sensing chip fabricated by the CMOS process has a small size, a simple structure, and In addition to sensing glucose, it can also be applied in many ways to sense the advantages of different biomolecules such as 11_MUA to adsorb antibiotic p0_yxin B as a sensing element, Ρί>_ΧΙη B to adsorb lipopolysaccharide (L-CCha_ 'It can be used as a lipopolysaccharide biosensor. So in the design of the wafer, in addition to sensing glucose, if the sensing element is a different transgenic or antibody antigen, it can be a paste-like wafer. Doing other biomolecule calls, so there is a lot of plasticity in the future _ on the way. To explain, but those skilled in the art can make various forms of changes without departing from the spirit of the present. The above embodiments are only used to illustrate the case and are not intended to limit the scope of the case. All kinds of modifications or changes are subject to the patent application scope of this case. [Simple description of the diagram] The first picture shows the design of the wafer in the case. The cross-section diagram of the finger-like measurement unit is the same. Schematic diagram of the cross-section of the photo-resistance of the unit. [S] 22 201209408 The fourth figure is a schematic diagram of the cross-section of the sensing unit to remove the photoresist. The fifth figure is a schematic diagram of the surface of the gold layer of the sensing unit. The sixth figure shows the intention of combining the sugar oxidase with (4) silk. The seventh figure is a schematic cross-sectional view of the combination of glucosinolates and glycosylated enzymes. The eighth figure shows the gold layer of the self-assembled single-layer film money measuring unit. ^The picture shows that Self assembled m_layer (SAM) will modify the earthen simmered essay (ii_mercaptoundeca her_, _mua)

Schematic diagram of the surface of the gold layer. The tenth figure is a schematic diagram of the RC oscillation circuit. The eleventh figure is the waveform of the \Λ point. For example, the twelfth figure is the waveform of point B. The twelfth picture shows the 乂(10) waveform diagram.

The fourteenth picture is a schematic diagram of the road. The fifteenth figure is the internal configuration diagram of the vibration i circuit of the case. The sixteenth figure is the waveform of the sewed electric sleeve. = Seven diagrams This figure refers to the relationship between the capacitance value of the fork electrode structure from 3 ^ to the f frequency curve and the corresponding relationship between the glucose concentration and the output frequency of the oscillation circuit 11_MUA and the output frequency of the domain circuit. Figure 19 Modification 11- Correspondence diagram of MUA/Grape ___. Comparison Figure Figure 20 shows the output frequency of modified glucose oxidase. Figure 20 - Figure of the fluorescence frequency of the glucose sensor. Twenty-second figure (4) Sugar concentration and quantity __ diagram. 23 201209408 [Description of main component symbols] 10- Sensing unit 11 - First metal layer 12 - Second metal layer 13 - Third metal layer 14 - Fourth metal layer 15 - Layer 16 - Gold layer 17 - Photoresist layer 21- Polymer 11-decyl undecanoic acid 22 - Glucose oxidase 23 - Glucose 30 - Sensing circuit 50 - Micro-crushed substrate • 60-Self-assembled single-layer film 61 - Part 1 62 - Part 2 Part 63 - Part III 64 - First Level 65 - Second Layer 66 - Third Layer

Claims (1)

201209408 VII. Patent application scope: 1. A miniature integrated biosensor, which mainly includes: - sensing unit ' _ on - micro-finance substrate; the _ unit is a capacitor money-pole structure, with a plurality of electrodes, The middle of the two electrodes is - Hao, the sensing area uses a gold layer as the sensing end of the biosensor; a polymer compound is modified on the surface of the gold layer to form a self-assembled monolayer film - a sensing element having a highly monolithic property for a specific substance is subjected to the surface of the self-assembled monolayer thin φ film to form a sensing film; the dielectric between the electrodes when the sensing film adsorbs a specific substance a coefficient is changed to cause a change in capacitance; a sensing circuit is coupled to the micro-germanium substrate and coupled to the sensing unit; the sensing circuit converts the capacitance change to a frequency output, thereby measuring the specific substance concentration. 2. The micro-integrated biosensor of claim 1, wherein the capacitive electrode structure of the sensing unit is composed of a finger-shaped electrode. 3. The micro-integrated biosensor according to claim 1, wherein the self-assembled φ single-layer film utilizes self-assembled monolayer film technology to repair the polymer compound in the gold layer. surface. 4. The micro-integrated biosensor as described in claim 1 of the patent application, Lv ', τ in the middle of the above-mentioned compound, the head group is an alkyl mercaptan. 5. The micro-integrated biosensor of claim 4, wherein the high molecular compound is a carboxyl group (-c〇〇H). 6. The micro-integrated biosensor of claim 4, wherein the high molecular compound has a biologically active functional group at the tail end. The micro-integrated biosensor of claim 1, wherein the sensing circuit is an oscillating circuit of an adjustable frequency output size. 8. The micro-integrated biosensor of claim 1, wherein the sensor is integrated on a portable carrier. 9. The micro-integrated biosensor of claim 1, wherein the sensing element is glucose oxsidase (GOD). 10. The micro-integrated biosensor of claim 1, wherein the sensing Φ element is an alternative to an enzyme, an antibody, an antigen, and an antibiotic adsorbing a lipopolysaccharide. m 26