TWI235237B - Biosensor, method of fabricating sensing unit thereof, and measuring system comprising the same - Google Patents

Abstract

A biosensor, a method of fabricating the sensing unit for the biosensor, and a measuring system comprising the biosensor. The biosensor has an extended gate field effect transistor (EGFET) structure and comprises a metal oxide semiconductor field effect transistor (MOSFET) on a semiconductor substrate, a sensing unit comprising a substrate, a silicon dioxide layer on the substrate, a tin oxide layer on the silicon dioxide layer, and a urease layer immobilized on the tin oxide layer, and an electric conductive wire connecting the MOSFET and the sensing unit.

Description

1235237 V. Description of the invention (1) '[Technical field to which the invention belongs] # This hairy month is related to an ion-sensing field-effect transistor, and in particular it is related to the development of an ion-sensing field-effect transistor. The sensing of the extended gate structure is that it has a urease film as a sensing film, which can be used to measure the acid-base or urea concentration of a solution. [Prior technology] Ion Sensitive Field Effect

(Transistor, ISFET) was first proposed by ρ Bergveld in 1970. The biggest difference from MOSFET is kISFET without metal gate electrode. It replaces the metal used by MOSFET with an ion sensing film that is difficult to invade by water and ionic substances. The oxide film uses the characteristic of the adsorption bond between the sensing film and the charged ions in the electrolyte aqueous solution to form an interface potential change between the sensing film and the electrolyte aqueous solution, thereby changing the FET channel current to measure the acidity of the aqueous solution. Base number or other ion concentration. ISFET was the first to use silicon dioxide as a pH sensing film, and later Al2O3, Si3N4, Ta05, and _2 were used as pH sensing films, because its pH sensing is better. In addition, JV D. Spiegel and others first proposed an Extended Gate Field Effect Transistor (EGFET) structure. The sensing film is located at the end of the signal line extending from the fet gate electrode. The film can be placed in the environment under test, and the FET can be protected from the chemical environment under test. '' And Janata and Moss first proposed the enzyme field effect transistor (Enzyme

Field Effect Transistor (EnFET) The outline of the structure of the sensing device ’is to select an appropriate enzyme film on the ion sensing membrane of ISFET. to

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In the earliest literature, it was used to detect pannisin. "丨 丨 丨 in", many EnFETs have been reported for urea, glucose, acetylcholine, and alcohol detection. The following is the relevant I SFET patents: 1. US Patent No. 4, 0 20, 830, inventor: Curtis C.

Johnson, Stanley D. Moss, Jirl A. Janata, Patent Bulletin Date: 1 977/0 5/03. This patent uses the diffusion principle to fix the chemical sensing film on the gate area of the field-effect ion sensing element. Chemical tests for diseases and enzymes. 2. US Patent No. 5, 350, 371, the inventor: Thomas P. Van 11 e η, the date of patent publication: 1 9 9 4/9/27. This patent is based on the chemical synthesis of Ehua-based sensing film on the gate area of the field-effect ion sensing element, which can detect the content of alkaline earth metals, especially for the detection of calcium ion content. 3. US Patent No. 5, 387, 328, the inventor. ByUngki

Sohn, Patent Publication Date: 1 995 / 1/7. This patent uses glucose immobilized on a sensing membrane for sensing glucose concentration, and uses platinum as a reference electrode. Using the turned metal as a reference electrode can detect all organic substances that can react with enzymes to produce 402, with high sensitivity and fast response time. 4. US Patent No. 4,812,220, Inventor: Ding 31 ^ 31 ^ 11〇13, Takeshi Kawabe, Patent Publication Date: 1 989/3/14. This patent uses enzymes to complete a% -effect ion sensing element to measure 3% of amino acids in food. Enzyme sensing can be miniaturized and low in amino acids

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It can also accurately measure the concentration. # 5 · US Patent No. 4,657,658, Inventor: Alastair ‘

Sjbbald, date of patent publication: 1 987/4/14. This patent uses a metal-oxide semiconductor transistor and a field-effect ion sensing element to form a differential module system, which can reduce the characteristics of its components (temperature, light, etc.). "," 6. US Patent No. 4,340, 458, Inventors: Harry Lerner, Jos D. Giner, John S. SoeldneF, Patent Publication Date · 1 982/7/20. This patent uses glucose sense = The measuring method is to connect the voltage of the circulating system to the test = / the current level of the tester can be used to study the concentration of the test solution. 7 · US Patent No. 4,927, 5 1 6 Inventor · Shuichir〇 Yamaguchi 'Takeshi Shimomura, date of patent announcement · 199 0/5/2 2. This patent is based on the development of an enzyme sensing element with a separated structure, and its measurement method can be carried out using a potentiometer or ammeter The membrane is immobilized on a separate structure. Li Qiao Er Enzyme 8. US Patent No. 4,900,423, the inventor: Ding 31 ^ Tu 丨 11 (13,

Takeshi Kawabe, Patent Publication Date: 1 990/2/13. This patent is based on the use of adenosine-5-triphosphate (ATP) chemical to immobilize enzymes in ion-sensing field effect transistors, which can be used for glucose pots for short periods of time and long-term stability. 9. U.S. Patent No. 5, 3 0 9, 085, Inventor: Byung ^ S ^ hn, date of patent publication · 1 994 / 5/3. This patent is based on the use of a differential amplifier circuit to develop a circuit for 'enzyme sensing, and its advantages are process technology.

1235237 V. Description of Invention (4) 10. United States, Patent No. 4,3 1 4,833, Inventor: Dieter

Kuppers, date of patent publication: 1 982/2/9. This patent uses a gallium oxide (GaAs) substrate to deposit a silicon thin film, and on this thin film "1-Shi Shenzi, prepares a low-resistance interlayer material to reduce the operating characteristics of scaled-off transistor components. Improve the current In the research, it is used to make ion-sensing field-effect film, such as: alumina (Al203), silicon nitride (SiA), pentaoxide (^^ 〇5), amorphous tungsten trioxide (wo. 3), and amorphous silicon hydride and tantalum, all use sputtering or plasma-assisted chemical vapor deposition.) The production cost of the film is expensive and the production time is long. An ion-sensing field-effect transistor with low cost, simple structure, and no sensing film and its sensing film. "..." [Summary of the Invention] In view of this, an object of the present invention is to provide a biosensor, ί ϋ Has extended gate field effect transistor structure, fast response time, = single, easy to manufacture and low cost, compared with traditional field effect transistors: good: stability, leakage current protection, and even a higher sense Sensitive and sensitive, can be reached at the solution pH i to ρΗ 9 58 mV / pH, good linearity L and a disposable sensor structure. ^ Another object of the invention is to provide a method for manufacturing a sensing element in the biological sensing of the present invention "b method In the gel-embedding method (gel e ^ t, rapmynt), the use of photopolymers to immobilize enzymes to ion sensing membranes is beneficial to the application of ion sensing field-effect transistors (ISFETs) to biomedical sensing / shellfish. Direct use of commercial Sn02 / Si02 / glass for direct fermentation

1235237 ------- V. Description of the invention (5) Enzyme sensing membrane The invention has low biological sense, and can be used to achieve the effect of the gate electrode to be tested on a semiconductor silicon film bit film, and The lead wire is connected to the board of the present invention; a film is formed on the dioxin to thin the above membranes and parts of the urease into a thin layer. The biosensor of the present invention has an electrode and an amplifier respectively, and the high impedance is manufactured according to 0, Another purpose of easy fabrication is to provide a measuring device. The sensor structure is discarded immediately, and there is no problem of liquid contamination with each other. For the above purpose, the crystal structure of the present invention is packaged on the substrate; a sensor element is on the substrate, and the cost is low. A measuring system having the present invention = part, due to easy production and long-term use, the enzyme is lost or the urea and the gold and oxygen are used to manufacture silicon dioxide thin pieces to prevent the wire film from the measuring device; One — The input and output terminals are connected with three electronic devices including gold alloy, tin oxide on the two body and the method, the conductive substrate on the substrate but the silicon film of the half field effect transistor fixed by the encapsulating enzyme film is exposed. On the film; covering the edge layer; and a gel system, a tin oxide film exposure system, including a reference electrode and an output sensor, with an extended oxygen half field effect transistor, including A substrate, a dioxygen film on the silicon dioxide tin oxide film; and a sensing element. The system includes the steps of forming a conductive substrate, a tin dioxide thin plate and a wire, and part of the tin dioxide thin layer to immobilize a urease. The scope of the first range of the terminal is connected; one is connected; and a table is connected to provide a stable end, the South impedance computer, to store some applications for the application of a fixed potential biosensor three electricity transmission and processing; * instrument amplification tester and The reference table, which communicates with the instrument interface card, or analysis data

1235237 V. Description of the invention (6) [Embodiment] Electro-mechanical measurement f is a type of extended inter-electrode ion-sensing field-effect extension Γ It is isolated by the idler epitaxial liquid of the ion-sensing field-effect transistor to avoid the semiconductor 7 ° The parts are completely soluble. The instability of the toad-free body parts and the partial gel-embedding method immobilized enzymes in the solution are formed into the sensing membrane to determine the hydrogen ion concentration or urea concentration of the solution. . Test ”: as shown in Figure 1a for further explanation. The biological sense of the present invention has an extended gate field effect transistor structure. The bean includes. ^ Two gold oxide half field effect power day and day body 112 (represented by a circuit), which is located on a half body base (not shown), and can be N-type or? Field effect transistor. A sensing element 106 is provided, which includes a substrate 101, a dioxide dioxide 2, a tin dioxide film 103, and a urinase enzyme film, an electrophoretic membrane, a transcript * ^ 1 / > Bingjing instantaneous membrane 109. The substrate may be a glass substrate and further an indium tin oxide (ITO) glass f. An emulsified silicon film can have a thickness of 100 0 Α to 200 0 Α, and the dioxide must be used as a buffer layer to enable SnO2 to grow on the glass directly at "2, and the film can have a thickness of 2 °°" Up to 3 °°° /: on: oxide film. Substrate, silicon dioxide film, and tin dioxide film 10 Ϊ iSn〇2 / SlO2 / glass film for easy production. The urease film is composed of a photopolymer and urease in a phosphate buffer solution #,: 5, and the ratio of the urea formase to the urease is better = 25, more preferably 25: κ 15: 1, and most preferably about 2. : 外部 t can be further covered with an insulating layer, ❹, epoxy resin, and only a part of the urease film is exposed to the test solution (not shown). Neighbor

1235237 V. Description of the invention (7), and wire 105, connected to the metal-oxygen half field-effect transistor 112, and the test element 110. The material of the wire can be metal. For example, the principle of ^ Ri body 112 ... Hai Wu will use the hydrogen ions attached to the sensing film to convert the principle of a field-effect transistor into an electrical signal. The channel width of a half field-effect transistor (FET) is wide, and the size of the current is used to learn that the concentration of hydrogen ions to be sensed is increased, so that a complete sensing is achieved. _ ί f / urea concentration in the test solution, when urea and urea on the sensing film = should be 'will hydrolyze 0H- or H + ions, extended gate ion sensing: the effect of f crystal will be on its PH value Generate a potential change ', and then from the electrical signal of the ion sensing field effect = crystal (jSFET) element, reflect the urea concentration in the solution to determine the urea concentration. The following is the hydrolysis reaction of urea: urease CO (NH2) 2 + 3H20 — C02 + 2NH4 + + 20H ~

According to the manufacturing method of the sensing element of the present invention, a conductive substrate is provided, a silicon dioxide film is formed on the substrate, and a tin dioxide film is formed on the stone dioxide film. These steps can be provided by purchasing a commercial SnOg / SiO〆 glass film, which simplifies the process, saves time and costs, or can be prepared on its own. Among them, the tin dioxide film can be grown on the stone dioxide film by chemical vapor deposition (CVD), and the growth temperature is 250 to 600 ° C, preferably 580 to 600 ° C. The film thickness is preferably 0.2 to 0.3, and the resistance value is 20 to 30 Ω / □. For example, using tin tetragas and water to make tin dioxide thin film, which

0619-10344TWF (Nl); patricia.ptd Page 11 1235237 V. Description of the invention (8) The reaction is shown by the following formula:.

The SnCl4 + 2H20-> Sn02 + 4HC1 silicon dioxide film can be grown by chemical vapor deposition at a temperature of preferably 580 to 600 t, which is thin and thick on the substrate, A. The thickness of the lead is preferably 100 to 300. Please refer to Figure lb to develop or obtain Sn0 tin dioxide film and a wire]. 5 is connected to η. 02 The layer is coated, but the exposed part of the tin dioxide is thin: the exposed part of the wire is made with a metal-oxygen half field, and then a urease is immobilized by a colloidal embedding method to form a urease membrane on the tin dioxide Over the exposed portion of the film. The colloidal embedding method is completed by mixing the photopolymer and urease in a phosphate buffer solution, photopolymerizing, and then placing it in a dark box at low temperature for a period of time: thereby immobilizing urease on the tin dioxide film on. The photopolymer is a polyvinyl alcohol photopolymer (poly (vinyl alcohol) bearing styrylpyridinium group (PVA-SbQ)), which may have phenylethyl dimethacrylate

Howl key base. The weight percentage range of the photopolymer to urease used is ⑼: ⑴ ... more preferably 25: 1 to 15: 1, and most preferably = circumference: V. For example, it can be 300mg / 100 // l PBS to 10mg / lOOvi pbs to 50 mg / 100 // l PBS to 10 mg / 100 / zl PBS, preferably 250 mg / 100 / z 1 PBS to 10 mg / 100 / z 1 PBS 20: 1 to 150 mg / l〇〇 # i pbs ratio

10mg / 100 / zl PBS range. During photopolymerization, urease (in a 5 mM phosphate buffer solution, pH 7) and photopolymer (at 5 mM

1235237 V. Description of the invention (9) in a phosphate buffered solution) The reaction is performed with light. The light used may be ultraviolet rays, such as ultraviolet light having a wavelength of 365 nm. After photopolymerization, the bio-products are allowed to stand in a dark box at a low temperature of 4 ° C to -10t for a period of time to complete the immobilization of urease on the tin dioxide film and complete the sensing. The production of each piece is shown in Figure 1c. Please note that during the colloidal embedding step, do not expose to white light to avoid photopolymerization of the enzyme itself. This sensing element can be placed directly in the test solution to determine the pH concentration.凊 Refer to FIG. 2, the above-mentioned biosensor is used to construct the measurement system of the present invention, and includes: a reference electrode 204, for example; a silver / silver chloride (Ag / AgC1) reference electrode, to provide stability Potential, and for comparison correction. It is also immersed in the solution when measuring the solution. An instrument amplifies state 2 0 2 to amplify and process the electric signal. It has two input terminals and one output terminal, and the two input terminals are connected to the biosensor 110 and the reference electrode 204 via wires 108 and 206, respectively. The instrumentation amplifier is a commercial IC LT1167. The connection between the biosensor 110 and the instrumentation amplifier 202 is detachable. For example, the biosensor 110 is electrically connected by a pin. In this way, after the measurement, the biosensor 110 can be discarded and replaced. An impedance dual-use meter 203 'is connected to the wheel output of the instrumentation amplifier 202 to read the output voltage value of the sensor 110. And a computer 205, which is connected to the high-impedance tri-meter 203 through a communication interface card 'for storing, processing, or analyzing data. Can be a personal computer. Communication interface card can use 82350 interface card. Can be used in a computer

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Use HP VEE program to control measurement variables and store data. You can further use Micro soft Origin 6. to analyze the output signal or draw a graph. "Measurement and Rishou" immerse the urea sensor film of the biosensor 丨 丨 〇 9 and the reference electrode in the test solution 201 (containing an acid-base solution or a urea solution). In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the preferred embodiments are exemplified below and described in detail as follows: Embodiment 1 Development of the biosensor of the present invention

A Sn〇2 / SiO2 glass film with a trade name of TO-30 3 0 was used. Use a diamond cutter to cut the Sn〇2 / Si〇2 / glass film into a 1cm x 1cm square, and then place it in an ultrasonic oscillator with deionized water and oscillate to remove the 5 scale remaining on the film. . The aluminum metal wire was adhered to Sn% / si0〆 with silver glue, and the glass film was placed in an oven for 120. 〇 Dry for 10 minutes, and wait for it to return to t2. Then pass the aluminum metal wire into the glass dropper or hair dropper 〇〇7, and the SnO〆Si 〇 2 / glass film and The dropper is fixed and placed in the baking phase at 120 ° C for 20 minutes. Next, the Sn02 / Si0, 2 / glass film was encapsulated with epoxy resin, leaving 1 · 5 with χ work. Sensing window, which is the extended gate sensing film, and the sensing film was connected to the metal-oxygen half field. 'Effective transistor' is a field effect transistor with an extended gate.

The delay-type gate ion field effect transistor was placed in a super-wave oscillator with deionized water and oscillated to remove the dirt remaining on the film. In addition, 'Polyvinyl alcohol photopolymer (pVA-SbQ) (Toyogo; manufactured by fgyo) was diluted to a concentration of 200 mg / 100 in a 5-phosphate buffer solution (PBS ), PH 70, and urease (EC 3.515, powder Type IV, from Jack bean, 50000 to 100,000 units / g,

1235237 V. Description of the invention (11),

Sigma Chemical Co., Ltd.) solution (concentration 10 mg / 100 in 5 mM PBS, pH 7.0) was mixed to prepare a mixture of urease and photopolymer. Finally, a 1 # 1 urease mixture was dropped on the sensing window. The device was exposed to ultraviolet light at 4W and 365nm, and the photopolymerization reaction was performed for about 20 minutes. Then place the element in a dark box at 4 ° C for about 12 hours, and then complete the production of urea sensing film on the extended gate ion sensing field effect transistor, as shown in Figure 1c. Embodiment 2 Architecture and measurement of the measurement system of the present invention Referring to FIG. 2, a biosensor 'developed as in the above embodiment 1 is used, which has a urease film as a sensing film. Connect the sensing film of the urea sensor to the input of the LT1167 with a wire, and connect the output of the LT1167 to the multi-meter. An Ag / AgCl reference electrode is used, which is also connected to the other input of the LT1167. Connect the multi-meter and personal computer through the communication interface card 82350. The application software of the HP VEE program is used to control the measured variables and stored data. The measured output data is processed and analyzed by Microsoft Origin 6.0. The architecture of the measurement system according to the present invention is completed. The measurement film and reference electrode need to be immersed in the solution to be measured. Use this measuring system to measure acid-base solutions with pH values of 1, 3, 5, 7, and 9. Change the gate voltage to obtain the output current. After processing and analyzing the data and data from Microsoft Origin 6.0, draw the output current vs. gate voltage curve. As shown in Figure 3a, take the appropriate current value IDS It is about 3 0 0 // A. It is known that the sensitivity is 58 mV / pH between pH 1 and pH 9. A graph of gate voltage vs. pH is also plotted, as shown in Figure 3b. Use this measurement system to measure 1.25 mg / dl, 10 mg / dl, 40

0619-10344TWF (N1); patricia.ptd Page 15 1235237 V. Description of the invention (12) Curves of mg / dl, 80 mg / dl and 120 output voltage versus measurement time Linearity of these sensors with urea solution The range shows that the material of the present invention is shown by the voltage difference on the urine result, and even the commercially available sensing film can be used, so the cost is low and the method of the present invention is used to make a bioelectric sensor. Furthermore, by using the urea sensor of the present invention to accurately measure the acid value or the urea readout circuit part in different acids and bases, the membrane can be contaminated and damaged. mg / dl five different urea solutions. Draw the line diagrams as shown in Figures 4a to 4e. The measured values obtained after linear correction were obtained between 5 mg / dl and 50 mg / dl, as shown in the graph of Figure 5 (ie, urea concentration). Indeed, the commercial products commonly used on SnOjSiO〆 glass film materials are used to make ions, easy to obtain, and simple to package. No one has ever tested the method and system of acid-base ion sensing field effect of the extended gate structure, and can accurately obtain the response curve of the urea solution. In addition, the sensor part and the component of the present invention can be discarded after being used, so as to avoid the sensing. Although the present invention has been disclosed in the preferred embodiments, the present invention is limited. Anyone who is familiar with this technique, but it is not used within the scope, should be able to make some changes and improvements without departing from the scope of the spirit of the present invention as the scope of the appended patent application. Therefore, the protection of the present invention shall prevail.

1235237 Brief description of the drawings Section 1a shows a structural cross-sectional view of a preferred embodiment of the extended closed-pole urea sensor element according to the present invention. No. 1 = The figure shows a sectional view of the structure of an extended gate ion sensing field effect according to the present invention. The electric signal Uf is not a package structure diagram of a preferred embodiment of the extended gate ion sensing field U-body assembly according to the present invention. > It shows the measurement system of a preferred embodiment of the extended gate urea sensor element according to the present invention. Figure 3a shows the output current (ids) versus gate voltage (Vg) curve of the measurement system according to the present invention at different values. Figure 3b shows the gate voltage (vG) vs. pH curve of the measurement system according to the present invention at different values. Figure 4a shows the relationship between the output voltage and time of the urea sensor when the urea solution is 1.25 mg / dl. Figure 4b shows the voltage and time relationship between the urea sensor and the urea solution at 10 m / d 1 in the wheel 4b. Figure 4c shows the graph of the relationship between wheel voltage and time of the urea sensor when the urea solution is 40 mg / dl. ^ Out Figure 4d shows the relationship between the voltage and time of the urea sensor in the urea solution. < f. Fig. 4e shows a graph of the urea dissolution voltage vs. time of the urea sensor at 120 mg / dl. Figure 5 shows the calibration curve of the urea solution measured by the measuring system from 1.25 mg / dl to 120.

0619-10344TWF (N1); patricia.ptd Page 17 1235237 Brief description of the drawings 101 Description of the substrate 101 Substrate 102 Silicon dioxide film 103 Tin dioxide film 104 Insulation layer 105 Wire 106 Sn02 / Si02 / Substrate 107 Glass dropper 108 ,, 20 6:: Lead wire 109 Urease sensing membrane 110 Biosensor 112 Metal oxide half field effect transistor 201 Test solution 202 Instrumentation amplifier 203 Dual-use meter 204 Ag / AgCl reference electrode 205 Personal computer

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Claims (1)

Time spent, gf 4 Na field effect transistor. 93109331 ___? Leap year / month // :: winifc " 1 · A biosensor, which has a body structure, including: A crystal, located in half the conductive sense The measuring element includes a substrate, a body substrate, a metal oxide half field effect substrate, a tin dioxide film and a silicon dioxide film located on the protease film and fixed on the tin dioxide film!丨, and a urine and a lead, connected to the metal-oxygen half-field-effect transistor 2. The sensing device as described in item 1 of the scope of patent application. A substrate, the: oxygen-cut film, and the dioxin, wherein the glass film. Thick version is Sn02 / Si02 glass 3 _ Shi Shen σ month patent scope of the biological metal oxide half field effect transistor system N type field effect transistor. One of them 4. The conductor described in item 1 of the patent scope is aluminum. The Tuguan U drama is, in which the biosensor described in the first item of the patent scope of the smell, the substrate is a conductive glass. /, T A n 6: The biosensor as described in item 5 of the patent application scope, wherein the substrate is an indium tin (ITO) glass. The biosensor according to item 1 of the scope of the patent application, wherein the urease / special membrane is fixed on the tin dioxide film by collapsing method. The biosensor according to item 7 of the scope of the patent application, wherein the urease 4 membrane is formed by mixing a photopolymer and urease in a phosphate buffer solution and photopolymerizing. Take ο rub 丨 ^^ No. 93109331 ", apply for a patent Qi Wai said: # 3_ ^ ^ A Affirmed that the biosensor described in item 8 of the patent Qianwei, Douzhong Xier polymer toilet brother. Yijiayuan The weight ratio of “10 ″ polar ice is about 30: 1 to 5: 1. It further includes-the biosensor as described in item 1 of the scope of patent application, wherein the 1 γ,, and 彖 layers are coated on the exterior of the sensing element. The bio-sensor plutonium layer described in item 10 of the patent application for delta delta is epoxy resin. • A method for manufacturing a sensing element, including the following steps k for a conductive substrate; forming a-^ forming-a silicon oxide film on the conductive substrate; a tin oxide film on the silicon dioxide film; -y- I oxidation connects the upper and lower package substrates with a wire; the thin parts of the tin are covered with an insulating layer, but the exposed part and the part, the wire of 1 knife; and the second bomb The urease method is used to immobilize a urease to form a urease film on the exposed part of the main membrane. According to the method of manufacturing sensing elements described in Item 12 of the η application patent, Fang Xiyi provides SnO2 / Si 02 glass film to provide the conductive substrate, α-H2O-Fossil film, And the tin dioxide film. Method, basin · The method of manufacturing a sensing element as described in item 12 of the patent application No. 2 in this method of colloidal embedding is to dissolve a photopolymer and urease in a monophosphoric acid solution, mix, and pass the light. Polymerization was completed in a low-temperature dark box for several days, so that urease was immobilized on the tin dioxide. 1, 15 · The method for manufacturing a sensing element as described in Item 14 of the declared patent scope, wherein the photopolymer is a polyvinyl alcohol photopolymer. 〇619-1〇344W1 (N1); Jyllu-ptc page 20 Case No. 9310933] Year "Ping ¥¥? ^ Wai. 1 6. The method for manufacturing a sensing element as described in item 15 of the scope of patent application, wherein the polyvinyl alcohol photopolymer has a styrylpyridine group. · 17 · The method for manufacturing a sensing element as described in item 14 of the scope of patent application, wherein the weight ratio of the photopolymer to urease is 30: 1 to 5:18, and the degree is 10 phosphate Method 19, Method 20, and Method 21 • The urease used in the method of manufacturing a sensing element as described in item 14 of the scope of patent application is in a 5 mM magnetic salt buffer solution, concentrated mg / 1 〇〇 // 1, the pH value is 7, the photopolymer used is in a 5 mM buffer solution, the concentration is 200 mg " 00 V 1, the pH value is 7. As described in item 14 of the scope of patent application The light used for the photopolymerization in the manufacturing method of the sensing element is ultraviolet light having a wavelength of 36.5 nm. • The low temperature is 4 ° C in the manufacturing method of the sensing element as described in item 14 of the patent application scope. A measurement system, comprising: a biosensor as in the first patent application scope; a reference electrode to provide a stable potential; The biological-instrumentation amplifier has two input terminals and a round-out sensor and the reference electrode is connected to the input terminal, respectively; and a 22-meter instrument is used to place a high-impedance three-meter meter, which is connected to the instrumentation amplifier. The computer's terminal is connected to the high-impedance II through a communication interface card—a meter i to store, process, or analyze data. • The measurement system described in item 21 of the scope of patent application, Its large device is LT1 1 67. 0619-10344T \ VFl (Nl); jyliu.ptc Page 21 I23523; tl case No. 93109331 is the amendment ^ six, the scope of the patent application which is 2 3. The measurement system as described in the scope of the patent application No. 21 Cang Kao electrode i / -gen / ^ Li, lg Yigen (Ag / AgCl) Dao electrode ° 2 4. The measurement system as described in item 21 of the patent application scope, wherein the computer is a personal computer. 25. The measurement system according to item 21 of the scope of patent application, wherein the communication interface card is 82350. 26. The measurement system described in item 21 of the scope of patent application, further using the HP VEE program to control measurement variables and store data. 27. According to the measurement system described in Item 26 of the scope of patent application, further use Micro so ft Origin 6.0 to analyze the output signal or # will output a graph. 0619-10344T \ VFl (Nl); jyliu.ptc Page 22