阅读说明：本技术 柔性电极及其制备方法、酶传感器及其制备方法 (Flexible electrode and preparation method thereof, enzyme sensor and preparation method thereof ) 是由 肖通方 杨瑶 李元光 于 2019-08-22 设计创作，主要内容包括：本发明提供一种柔性电极及其制备方法、酶传感器及其制备方法。该柔性电极包括：对电极,对电极的表面固定有一体连接的高分子膜；高分子膜上固定有工作电极和参比电极。本发明可以获得具有稳定性、可靠性和一致性的柔性电极和酶传感器,降低了制备成本,对于血糖持续监测和糖尿病的动态分析管理具有重要意义。(the invention provides a flexible electrode and a preparation method thereof, and an enzyme sensor and a preparation method thereof. The flexible electrode includes: the surface of the counter electrode is fixed with an integrally connected polymer film; the working electrode and the reference electrode are fixed on the polymer membrane. The invention can obtain the flexible electrode and the enzyme sensor with stability, reliability and consistency, reduces the preparation cost and has important significance for continuous monitoring of blood sugar and dynamic analysis and management of diabetes.)

1. A flexible electrode, comprising:

The surface of the counter electrode is fixed with an integrally connected polymer film;

And a working electrode and a reference electrode are fixed on the polymer membrane.

2. the flexible electrode of claim 1,

The counter electrode is a sheet electrode or a columnar electrode;

when the counter electrode is a sheet electrode, the working electrode is opposite to the reference electrode;

When the counter electrode is a columnar electrode, the working electrode and the reference electrode are staggered and parallel.

3. the flexible electrode of claim 1,

The counter electrode is platinum;

the working electrode is gold or platinum;

the reference electrode comprises silver and silver chloride.

4. The flexible electrode of claim 1,

The polymer film comprises one or any combination of polyester, polyvinylidene fluoride, polytetrafluoroethylene and polyimide.

5. the flexible electrode of claim 1, further comprising:

A first conductive trace and a second conductive trace disposed on the polymeric film;

one end of the first conductive trace is connected with the working electrode, and the other end of the first conductive trace is connected with an external detector;

One end of the second conductive trace is connected with the reference electrode, and the other end of the second conductive trace is connected with the external detector.

6. A method for preparing a flexible electrode is characterized by comprising the following steps:

Providing a polymer film;

respectively forming a working electrode and a reference electrode on one surface of the polymer membrane;

and folding the polymer film, wherein the working electrode and the reference electrode are oppositely fixed on the surface of the folded polymer film.

7. The method for preparing a flexible electrode according to claim 6, further comprising, after forming the working electrode and the reference electrode on one surface of the polymer film, respectively;

two conductive traces are formed on the face that are connected to the working electrode and the reference electrode, respectively.

8. the method of claim 7, wherein forming the conductive trace comprises:

Photolithography, vapor deposition, sputtering, or dispensing.

9. The method for preparing a flexible electrode according to claim 6, wherein the forming of the working electrode and the reference electrode on one surface of the polymer film respectively comprises:

Forming a working electrode region on one side of the polymer film;

Fixing gold or platinum on the working electrode area to form a working electrode;

Forming a reference electrode region on the surface of the polymer film;

Immobilizing silver on the reference electrode region;

the silver is chloridized to form a reference electrode.

10. the method for manufacturing a flexible electrode according to claim 9,

The manner of forming the working electrode region or forming the reference electrode region includes: photoetching or mask etching;

the means for immobilizing gold or platinum on the working electrode region, or silver on the reference electrode region comprises: sputtering or vapor deposition.

11. A method for preparing a flexible electrode is characterized by comprising the following steps:

providing a counter electrode and a polymer film;

respectively forming a working electrode and a reference electrode on one surface of the polymer membrane;

fixing the polymer film on the surface of the counter electrode; wherein the working electrode and the reference electrode are positioned on the surface of the fixed polymer membrane.

12. the method for manufacturing a flexible electrode according to claim 11,

when the counter electrode is a sheet electrode, folding the polymer film and fixing the folded polymer film on the surface of the counter electrode; the working electrode and the reference electrode are oppositely fixed on the surface of the folded polymer film;

when the counter electrode is a columnar electrode, the polymer film is fixed on the surface of the counter electrode after being rolled; wherein the working electrode and the reference electrode are staggered and parallel on the surface of the rolled polymer film.

13. The method for preparing a flexible electrode according to claim 11, further comprising, after forming the working electrode and the reference electrode on one surface of the polymer film, respectively;

two conductive traces are formed on the face that are connected to the working electrode and the reference electrode, respectively.

14. the method of claim 13, wherein forming the conductive trace comprises:

Photolithography, vapor deposition, sputtering, or dispensing.

15. the method of claim 11, wherein the forming the working electrode and the reference electrode on one surface of the polymer film respectively comprises:

Forming a working electrode region on one side of the polymer film;

Fixing gold or platinum on the working electrode area to form a working electrode;

Forming a reference electrode region on the surface of the polymer film;

Immobilizing silver on the reference electrode region;

The silver is chloridized to form a reference electrode.

16. the method of manufacturing a flexible electrode according to claim 15,

the manner of forming the working electrode region or forming the reference electrode region includes: photoetching or mask etching;

the means for immobilizing gold or platinum on the working electrode region, or silver on the reference electrode region comprises: sputtering or vapor deposition.

17. An enzyme sensor, comprising:

the flexible electrode of any one of claims 1 to 5;

An enzyme layer on the working electrode of the flexible electrode.

18. the enzyme sensor according to claim 17, further comprising:

An anti-interference layer;

The anti-interference layer is positioned on the surfaces of the flexible electrode and the enzyme layer.

19. the enzyme sensor according to claim 18, further comprising:

A diffusion-suppressing layer;

the diffusion inhibiting layer is positioned on the surface of the anti-interference layer.

20. a method of making an enzyme sensor, comprising:

preparing a flexible electrode using the flexible electrode preparation method of any one of claims 6 to 10; or, a flexible electrode is manufactured by using the flexible electrode manufacturing method of any one of claims 11 to 16;

and modifying an enzyme solution on a working electrode of the flexible electrode to obtain the enzyme sensor.

21. The method of manufacturing an enzyme sensor according to claim 20, further comprising, after obtaining the enzyme sensor:

and modifying the anti-interference layer solution on the surface of the enzyme sensor to form an anti-interference layer.

22. the method for manufacturing an enzyme sensor according to claim 21, further comprising, after the step of forming the interference prevention layer:

And modifying the diffusion inhibition layer solution on the surface of the anti-interference layer to form a diffusion inhibition layer.

23. the method of manufacturing an enzyme sensor according to claim 20, further comprising:

And mixing glucose oxidase, bovine serum albumin and glutaraldehyde, and then carrying out full cross-linking reaction to obtain the enzyme solution.

24. the method of manufacturing an enzyme sensor according to claim 23,

The concentration of the glucose oxidase is 5mg/mL to 10 mg/mL;

The mass fraction of the glutaraldehyde is 0.05%.

25. The method of manufacturing an enzyme sensor according to claim 23,

The modification mode of the enzyme solution comprises dripping or soaking.

26. the method of manufacturing an enzyme sensor according to claim 21,

the anti-interference layer solution is a perfluorosulfonic acid polymer solution or a cellulose acetate solution;

The solution concentration of the anti-interference layer solution is 1-5%.

27. The method of manufacturing an enzyme sensor according to claim 22,

The diffusion inhibition layer solution comprises one or any combination of a cellulose acetate solution, a polyurethane solution, a polyvinyl alcohol solution or a polycarbonate solution;

the solution concentration of the diffusion inhibition layer solution is 1% to 5%.

Technical Field

The invention relates to the technical field of sensor electrode manufacturing, in particular to a flexible electrode and a preparation method thereof, and an enzyme sensor and a preparation method thereof.

background

blood sugar monitoring is an important component in diabetes management, and the result of the blood sugar monitoring is helpful for evaluating the sugar metabolism disorder degree of a diabetic patient, formulating a reasonable blood sugar reduction scheme and preventing and reducing the generation of complications. Most of the traditional blood sugar monitoring adopts a blood sugar test strip to detect the concentration of peripheral blood sugar, namely blood sugar measurement. However, for some serious diabetics and those who have to frequently check the glucose level in the body to regulate the glucose intake in their diets, frequent blood glucose measurements can cause great pain, and the data is still relatively single, so that the blood glucose cannot be further finely managed, and sometimes it is difficult to find asymptomatic hyperglycemia and hypoglycemia. Continuous dynamic blood Glucose monitoring system (CGMS) allows for uninterrupted 24-hour measurement of changes in Glucose concentration in a human body by wearing a Glucose sensor on the surface of the skin of a patient or implanting a Glucose sensor in the subcutaneous tissue. Such systems record glucose values on average every few minutes or less, thereby forming a trend of daily blood glucose maps. And it can catch the peripheral blood sugar can't find unknown relevant information such as hypoglycemia, postprandial blood sugar peak value, hyperglycemia duration, etc., help the patient to know the change situation of self blood sugar more, can offer the most scientific basis for the clinician to choose the medicament, judge the curative effect, formulate the rational dietary structure.

Most sensors for continuous glucose monitoring are prepared based on electrochemical amperometric detection electrodes of glucose oxidase. These enzyme-type sensors detect the electron transfer that occurs when the enzyme catalyzes glucose, thereby forming a measurable current signal based on which the corresponding glucose concentration in the body is given. In general, a dynamic blood glucose monitor attached to the skin surface mainly uses an osmosis method to make glucose permeate from subcutaneous tissue fluid or blood vessels, and an electrochemical sensor on the skin surface is used to detect the glucose, so as to indirectly reflect the change of the glucose concentration in the tissue fluid or blood vessels. However, the monitor is subjected to large external interference, and the detection accuracy still faces a great challenge. The direct implantation of glucose sensors into subcutaneous tissue to measure glucose concentration changes in interstitial fluid is the major trend in dynamic blood glucose. The sensor directly detects glucose in interstitial fluid under the skin to avoid external interference, and the sensor has better consistency with blood glucose change. However, when the implantable glucose sensor is used for detection, the convenience, safety and reliability of use need to be satisfied, and besides, the implantable electrode part also needs to have high biocompatibility so as not to bring inflammation or biological toxicity to an individual. If the implanted electrode causes serious inflammation and rejection reaction, the biochemical microenvironment of body tissues around the electrode can be changed, and the detection result of the electrode is further influenced. Therefore, the shape, size, and material of the substrate of the electrode to be tested are important, and an excessively large electrode size or an electrode material with poor biocompatibility may cause poor experience and other unexpected damage to the patient during long-term implantation. The solution of some dynamic blood sugar monitoring products is to use a relatively hard stainless steel needle as an electrode substrate material to construct an enzyme electrode, although the enzyme electrode can be directly implanted into subcutaneous tissue without the assistance of an external auxiliary device, the hard electrode material can also extremely initiate inflammatory reaction. The Pt wire directly adopting the micrometer scale has better biocompatibility, and the working electrode for detection is relatively easy to prepare by taking the Pt wire as the electrode substrate, but the difficulty of further integrating the counter electrode and the reference electrode on the Pt wire substrate is higher, and the challenges of further expanding implantation damage, poor patient experience and the like can be met by adopting two or more Pt wire electrodes to be implanted simultaneously. The flexible and foldable high-molecular insulating substrate materials are widely concerned, ordered processing is easy to carry out on the high-molecular film materials, and micro-nano-sized electrodes constructed on the basis are more beneficial to implantation and long-term subcutaneous detection. However, the size requirement of the flexible implanted electrode is high, and integration of three electrodes, namely a working electrode, a reference electrode and a counter electrode is faced, so that the design, preparation and further processing of the electrode face the significant challenge, the subsequent modification of a sensing layer of the electrode is more difficult, and the consistency, reliability, stability and manufacturing cost of the electrode are inevitably affected.

Disclosure of Invention

The embodiment of the invention mainly aims to provide a flexible electrode and a preparation method thereof so as to obtain the flexible electrode with stability, reliability and consistency and reduce the preparation cost.

In order to achieve the above object, an embodiment of the present invention provides a flexible electrode, including:

the surface of the counter electrode is fixed with an integrally connected polymer film;

The working electrode and the reference electrode are fixed on the polymer membrane.

in one embodiment, the counter electrode is a sheet electrode or a columnar electrode;

When the counter electrode is a sheet electrode, the working electrode is opposite to the reference electrode;

When the counter electrode is a columnar electrode, the working electrode and the reference electrode are staggered and parallel.

In one embodiment, the counter electrode is platinum;

the working electrode is gold or platinum;

the reference electrode comprises silver and silver chloride.

In one embodiment, the polymer film comprises one or any combination of polyester, polyvinylidene fluoride, polytetrafluoroethylene, and polyimide.

in one embodiment, the method further comprises the following steps:

a first conductive trace and a second conductive trace disposed on the polymeric film;

one end of the first conductive trace is connected with the working electrode, and the other end of the first conductive trace is connected with an external detector;

one end of the second conductive trace is connected to the reference electrode and the other end is connected to an external detector.

The embodiment of the invention also provides a first preparation method of the flexible electrode, which comprises the following steps:

Providing a polymer film;

Respectively forming a working electrode and a reference electrode on one surface of the polymer film;

And folding the polymer film, and fixing the working electrode and the reference electrode on the surface of the folded polymer film in an opposite manner.

in one embodiment, after the working electrode and the reference electrode are respectively formed on one side of the polymer membrane, the method further comprises the following steps;

Two conductive traces are formed on the face that are connected to the working and reference electrodes, respectively.

in one embodiment, the manner of forming the conductive traces includes:

Photolithography, vapor deposition, sputtering, or dispensing.

In one embodiment, the forming of the working electrode and the reference electrode on one side of the polymer membrane respectively comprises:

Forming a working electrode region on one side of the polymer film;

fixing gold or platinum on the working electrode area to form a working electrode;

forming a reference electrode region on the surface of the polymer film;

immobilizing silver on the reference electrode region;

The silver is chloridized to form a reference electrode.

in one embodiment, the manner of forming the working electrode region or forming the reference electrode region includes: photoetching or mask etching;

the manner of immobilizing gold or platinum on the working electrode area, or silver on the reference electrode area includes: sputtering or vapor deposition.

the embodiment of the invention also provides a second preparation method of the flexible electrode, which comprises the following steps:

Providing a counter electrode and a polymer film;

Respectively forming a working electrode and a reference electrode on one surface of the polymer film;

Fixing the polymer film on the surface of the counter electrode; wherein, the working electrode and the reference electrode are positioned on the surface of the fixed polymer film.

in one embodiment, when the counter electrode is a sheet electrode, the polymer film is folded and fixed on the surface of the counter electrode; wherein, the working electrode and the reference electrode are oppositely fixed on the surface of the folded polymer film;

When the counter electrode is a columnar electrode, the polymer film is fixed on the surface of the counter electrode after being rolled; wherein, the working electrode and the reference electrode are staggered and parallel on the surface of the rolled polymer film.

In one embodiment, after the working electrode and the reference electrode are respectively formed on one side of the polymer membrane, the method further comprises the following steps;

Two conductive traces are formed on the face that are connected to the working and reference electrodes, respectively.

In one embodiment, the manner of forming the conductive traces includes:

photolithography, vapor deposition, sputtering, or dispensing.

In one embodiment, the forming of the working electrode and the reference electrode on one side of the polymer membrane respectively comprises:

Forming a working electrode region on one side of the polymer film;

Fixing gold or platinum on the working electrode area to form a working electrode;

forming a reference electrode region on the surface of the polymer film;

immobilizing silver on the reference electrode region;

The silver is chloridized to form a reference electrode.

In one embodiment, the manner of forming the working electrode region or forming the reference electrode region includes: photoetching or mask etching;

The manner of immobilizing gold or platinum on the working electrode area, or silver on the reference electrode area includes: sputtering or vapor deposition.

the flexible electrode and the preparation method thereof provided by the embodiment of the invention can obtain the flexible electrode with stability, reliability and consistency, reduce the preparation cost and have important significance for continuous monitoring of blood sugar and dynamic analysis and management of diabetes.

an embodiment of the present invention further provides an enzyme sensor, including:

A flexible electrode as described above;

and the enzyme layer is positioned on the working electrode of the flexible electrode.

In one embodiment, the method further comprises the following steps:

An anti-interference layer;

the anti-interference layer is positioned on the surfaces of the flexible electrode and the enzyme layer.

In one embodiment, the method further comprises the following steps:

a diffusion-suppressing layer;

the diffusion inhibiting layer is positioned on the surface of the anti-interference layer.

the embodiment of the invention also provides a preparation method of the enzyme sensor, which comprises the following steps:

Preparing a flexible electrode using the first preparation method of a flexible electrode as described above; or, preparing a flexible electrode by using the second preparation method of the flexible electrode;

And modifying the enzyme solution on a working electrode of the flexible electrode to obtain the enzyme sensor.

In one embodiment, after obtaining the enzyme sensor, the method further comprises:

And modifying the anti-interference layer solution on the surface of the enzyme sensor to form an anti-interference layer.

In one embodiment, after the formation of the interference rejection layer, the method further includes:

And modifying the diffusion inhibition layer solution on the surface of the anti-interference layer to form a diffusion inhibition layer.

in one embodiment, the method further comprises the following steps:

mixing glucose oxidase, bovine serum albumin and glutaraldehyde, and then carrying out full cross-linking reaction to obtain an enzyme solution.

in one embodiment, the glucose oxidase is at a concentration of 5mg/mL to 10 mg/mL;

The mass fraction of glutaraldehyde was 0.05%.

In one embodiment, the enzyme solution is modified by dipping or soaking.

In one embodiment, the anti-interference layer solution is a perfluorosulfonic acid polymer solution or a cellulose acetate solution;

the solution concentration of the anti-interference layer solution is 1 to 5 percent.

In one embodiment, the diffusion inhibition layer solution comprises one or any combination of a cellulose acetate solution, a polyurethane solution, a polyvinyl alcohol solution, or a polycarbonate solution;

The solution concentration of the diffusion suppressing layer solution is 1% to 5%.

the enzyme sensor and the preparation method thereof provided by the embodiment of the invention can obtain the enzyme sensor with stability, reliability and consistency, reduce the preparation cost and have important significance for continuous monitoring of blood sugar and dynamic analysis and management of diabetes.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

FIG. 1 is a top view of a flexible electrode according to a first embodiment of the present invention;

FIG. 2 is a side view of a flexible electrode in a first embodiment of the invention;

FIG. 3 is a front view of a flexible electrode in a second embodiment of the invention;

FIG. 4 is a top view of a flexible electrode according to a second embodiment of the present invention;

FIG. 5 is a flow chart of a first method of making a flexible electrode according to an embodiment of the present invention;

FIG. 6 is a schematic illustration of the fabrication of a flexible electrode in one embodiment of the present invention;

FIG. 7 is a top view of a flexible electrode according to a third embodiment of the present invention;

FIG. 8 is a side view of a flexible electrode in a third embodiment of the invention;

FIG. 9 is a flow chart of a second method of making a flexible electrode according to an embodiment of the present invention;

FIG. 10 is a schematic illustration of the fabrication of a flexible electrode in another embodiment of the present invention;

FIG. 11 is a schematic illustration of the fabrication of a flexible electrode according to yet another embodiment of the present invention;

FIG. 12 is a front view of a third embodiment of the present invention before being rolled;

FIG. 13 is a flow chart of a method of making an enzyme sensor according to one embodiment of the invention;

FIG. 14 is a time-line plot of three electrodes of an enzyme sensor versus glucose in one embodiment of the present invention;

FIG. 15 is a linear plot of the concentration of glucose versus the three electrodes of the enzyme sensor in one embodiment of the present invention;

FIG. 16 is a graph of the interference rejection of an enzyme sensor for glucose in accordance with an embodiment of the present invention;

FIG. 17 is a graph showing the stability of an enzyme sensor over time in one embodiment of the present invention.

Detailed Description

the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

the experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

The materials, reagents and the like used in the examples of the present invention are commercially available unless otherwise specified.

In view of the difficulties in designing, preparing and processing the flexible electrode in the prior art and the difficulties in modifying the subsequent sensing layer of the flexible electrode, the embodiment of the invention provides the flexible electrode and the preparation method thereof, the enzyme sensor and the preparation method thereof, so as to obtain the flexible electrode and the enzyme sensor with stability, reliability and consistency, reduce the preparation cost and have important significance in continuous monitoring of blood sugar and dynamic analysis and management of diabetes. The present invention will be described in detail below with reference to the accompanying drawings.

The flexible electrode of the embodiment of the invention comprises: a polymer film 2 which is integrally connected is fixed on the surface of the counter electrode 1; a working electrode 3 and a reference electrode 4 are fixed to the polymer membrane 2. The length of the flexible electrode is 0.5cm-2 cm.

in one embodiment, the counter electrode 1 is made of platinum and is connected with an external detector through an exposed part of the top end, the working electrode 3 is made of gold or platinum, the reference electrode 4 comprises silver and silver chloride, the polymer membrane 2 comprises one or any combination of polyester, polyvinylidene fluoride, polytetrafluoroethylene and polyimide, the thickness of the polymer membrane 2 can be about 0.01mm-0.05mm, the length of the working electrode 3 and the length of the reference electrode 4 are both 0.5cm-1.5cm, the width of the working electrode 3 and the width of the reference electrode 4 are both 0.1mm-0.3mm, and the area of the working electrode 3 and the reference electrode 4 are both 0.05mm ² -0.45mm ².

FIG. 1 is a top view of a flexible electrode according to a first embodiment of the present invention. Fig. 2 is a side view of a flexible electrode in a first embodiment of the invention. As shown in fig. 1 to 2, when the counter electrode 1 is a sheet electrode, the working electrode 3 faces the reference electrode 4. The counter electrode 1 has a thickness of 0.01mm to 0.05mm and a length of about 1mm in which the polymer film 2 is exposed.

Fig. 3 is a front view of a flexible electrode in a second embodiment of the invention. Fig. 4 is a top view of a flexible electrode in a second embodiment of the invention. As shown in fig. 3 to 4, when the counter electrode 1 is a columnar electrode, the working electrodes 3 are parallel to the reference electrodes 4 in a staggered manner. The counter electrode 1 has a diameter of 0.01 to 0.05mm and a length of about 1mm in which the polymer film 2 is exposed.

in one embodiment, the counter electrode is platinum, the working electrode is gold or platinum, and the reference electrode comprises silver and silver chloride.

as shown in fig. 1 to 4, the flexible electrode further includes: a first conductive trace 5 and a second conductive trace 6 disposed on the polymer film 2; one end of the first conductive trace 5 is connected with the working electrode 3, and the other end is connected with an external detector; one end of the second conductive trace 6 is connected to the reference electrode 4 and the other end is connected to an external detector.

Wherein the first conductive trace 5 and the second conductive trace 6 may extend to the ends of the polymer film 2, respectively, and form a conductive disk, which is connected to an external detector. The diameter of the conductive disc may be 2 mm. The first conductive trace 5 and the second conductive trace 6 each include: silver, gold, and carbon. The first conductive trace 5 and the second conductive trace 6 each have a length of 5mm to 10mm and a width of 0.1mm to 0.2 mm.

FIG. 5 is a flow chart of a first method of fabricating a flexible electrode according to an embodiment of the present invention. FIG. 6 is a schematic illustration of the fabrication of a flexible electrode in one embodiment of the present invention. As shown in fig. 5 to 6, an embodiment of the present invention further provides a first method for manufacturing a flexible electrode, including:

S101: a polymeric membrane is provided.

S102: and respectively forming a working electrode and a reference electrode on one surface of the polymer membrane.

Wherein, S102 includes: forming a working electrode area on one surface of the polymer film in a photoetching or mask etching mode; fixing gold or platinum on the working electrode area by sputtering or vapor deposition to form a working electrode;

forming a reference electrode area on the surface of the polymer film in a photoetching or mask etching mode; fixing silver on the reference electrode area by means of sputtering or vapor deposition; the silver is chloridized to form a reference electrode. Wherein silver can be chlorinated in potassium perchlorate solution to form a silver chloride layer.

s103: and folding the polymer film, and fixing the working electrode and the reference electrode on the surface of the folded polymer film in an opposite manner.

In an embodiment, after executing S102, the method may further include: two conductive traces are formed on the face that are connected to the working and reference electrodes, respectively. In specific implementation, silver, gold, carbon and other substances can be deposited on the polymer film by means of photolithography, vapor deposition, sputtering, dropping coating or the like to form a conductive trace, and further insulate the conductive trace.

S103 specifically comprises the following steps: and uniformly coating epoxy resin on the other surface of the polymer film, and folding the polymer film in half from the middle position to obtain the flexible electrodes with detection areas distributed on the front surface and the back surface.

The first preparation method of the flexible electrode comprises the following specific processes:

1. a polymeric membrane is provided.

2. Forming a working electrode area on one side of one surface of the polymer film in a photoetching or mask etching mode; the working electrode is formed by fixing gold or platinum on the working electrode area by means of sputtering or vapor deposition.

3. Forming a reference electrode area on the other side of the surface of the polymer film in a photoetching or mask etching mode; fixing silver on the reference electrode area by means of sputtering or vapor deposition; the silver is chlorinated in potassium perchlorate solution to form a silver chloride layer.

4. And depositing silver, gold, carbon and other substances on the polymer film by means of photoetching, vapor deposition, sputtering or dripping and the like to form two conductive traces respectively connected with the working electrode and the reference electrode, and further insulating the conductive traces.

5. And uniformly coating epoxy resin on the other surface of the polymer film, folding the polymer film in half from the middle position, and fixing the working electrode and the reference electrode on the surface of the folded polymer film in a relative manner.

fig. 7 is a top view of a flexible electrode in a third embodiment of the invention. FIG. 8 is a side view of a flexible electrode in a third embodiment of the invention. As shown in fig. 7 to 8, by the above steps, a flexible electrode for blood glucose monitoring having a working electrode and a reference electrode can be constructed using only a polymer membrane. The flexible electrode comprises a polymer membrane 2, a working electrode 3, a reference electrode 4, a first conductive trace 5 and a second conductive trace 6. A working electrode 3 and a reference electrode 4 which are oppositely arranged are fixed on the folded polymer membrane 2, one end of a first conductive trace 5 is connected with the working electrode 3, and the other end is connected with an external detector; one end of the second conductive trace 6 is connected to the reference electrode 4 and the other end is connected to an external detector. The length of the working electrode 3 and the reference electrode 4 is 0.5cm-1.5cm, and the width thereof is 0.1mm-0.3 mm. The length of the flexible electrode is 0.5cm-2 cm.

FIG. 9 is a flow chart of a second method for fabricating a flexible electrode according to an embodiment of the present invention. As shown in fig. 9, the second preparation method of the flexible electrode includes:

s201: a counter electrode and a polymer film are provided.

s202: and respectively forming a working electrode and a reference electrode on one surface of the polymer membrane.

wherein, S202 includes: forming a working electrode area on one surface of the polymer film in a photoetching or mask etching mode; fixing gold or platinum on the working electrode area by sputtering or vapor deposition to form a working electrode;

Forming a reference electrode area on the surface of the polymer film in a photoetching or mask etching mode; fixing silver on the reference electrode area by means of sputtering or vapor deposition; the silver is chloridized to form a reference electrode.

s203: fixing the polymer film on the surface of the counter electrode; wherein, the working electrode and the reference electrode are positioned on the surface of the fixed polymer film.

FIG. 10 is a schematic illustration of the fabrication of a flexible electrode in another embodiment of the present invention. As shown in fig. 10, when the counter electrode 1 is a sheet electrode, the polymer film 2 is folded and fixed on the surface of the counter electrode 1; wherein, the working electrode 3 and the reference electrode 4 are fixed on the surface of the folded polymer film 2 oppositely. Before the polymer membrane 2 is folded, the working electrode 3 and the reference electrode 4 are respectively positioned at two sides of the polymer membrane 2; the two sides of the counter electrode 1 are coated with sticky epoxy resin, and then the polymer film 2 is folded by taking the counter electrode 1 as a supporting center, so that the polymer film 2 can be firmly adhered to the surface of the counter electrode 1 to obtain two electrodes (a working electrode 3 and a reference electrode 4) on the front side and the back side, implantation in a small area can be realized, the whole size of the flexible electrode can be reduced, and the flexible electrode has high detection sensitivity. Further, the counter electrode 1 serves as a substrate of the flexible electrode: the supporting material of the polymer film 2 enables the flexible electrode to keep proper toughness.

when the counter electrode is a sheet electrode, the specific flow of the second preparation method of the flexible electrode is as follows:

1. A counter electrode and a polymer film are provided.

2. forming a working electrode area on one side of one surface of the polymer film in a photoetching or mask etching mode; the working electrode is formed by fixing gold or platinum on the working electrode area by means of sputtering or vapor deposition.

3. Forming a reference electrode area on the other side of the surface of the polymer film in a photoetching or mask etching mode; fixing silver on the reference electrode area by means of sputtering or vapor deposition; the silver is chlorinated in potassium perchlorate solution to form a silver chloride layer.

4. and depositing silver, gold, carbon and other substances on the polymer film by means of photoetching, vapor deposition, sputtering or dripping and the like to form two conductive traces respectively connected with the working electrode and the reference electrode, and further insulating the conductive traces.

5. And (3) coating adhesive epoxy resin on both surfaces of the counter electrode, then folding the polymer film by taking the counter electrode 1 as a supporting center, and firmly adhering the polymer film to the surface of the counter electrode 1. The working electrode and the reference electrode are positioned on the surface of the fixed polymer membrane to form the flexible electrode shown in fig. 1 to 2.

FIG. 11 is a schematic illustration of the fabrication of a flexible electrode in accordance with yet another embodiment of the present invention. FIG. 12 is a front view of a third embodiment of the present invention before being wound on a roll. As shown in fig. 11 to 12, when the counter electrode 1 is a columnar electrode, the epoxy resin is uniformly coated on the counter electrode 1, and then the polymer film 2 is fixed on the surface of the counter electrode 1 after being rolled; the working electrode 3 and the reference electrode 4 are alternately parallel to each other on the surface of the rolled polymer film 2. Further, the counter electrode 1 serves as a substrate of the flexible electrode: the supporting material of the polymer film 2 enables the flexible electrode to keep proper toughness.

In an embodiment, after performing S202, the method may further include: two conductive traces are formed on the face that are connected to the working and reference electrodes, respectively. Ways of forming the conductive traces include: photolithography, vapor deposition, sputtering, or dispensing.

When the counter electrode is a columnar electrode, the specific flow of the second preparation method of the flexible electrode is as follows:

1. A counter electrode and a polymer film are provided.

2. Forming a working electrode area on one side of one surface of the polymer film in a photoetching or mask etching mode; the working electrode is formed by fixing gold or platinum on the working electrode area by means of sputtering or vapor deposition.

3. Forming a reference electrode area on the other side of the surface of the polymer film in a photoetching or mask etching mode; fixing silver on the reference electrode area by means of sputtering or vapor deposition; the silver is chlorinated in potassium perchlorate solution to form a silver chloride layer.

4. And depositing silver, gold, carbon and other substances on the polymer film by means of photoetching, vapor deposition, sputtering or dripping and the like to form two conductive traces respectively connected with the working electrode and the reference electrode, and further insulating the conductive traces.

5. winding a polymer film shaft and fixing the polymer film shaft on the surface of the counter electrode; the working electrode and the reference electrode are staggered and parallel on the surface of the rolled polymer film to form the flexible electrode shown in fig. 3 to 4.

in conclusion, the flexible electrode and the preparation method thereof provided by the embodiment of the invention can obtain the flexible electrode with stability, reliability and consistency, reduce the preparation cost and have important significance for continuous monitoring of blood sugar and dynamic analysis and management of diabetes.

An embodiment of the present invention further provides an enzyme sensor, including: a flexible electrode as described above; and the enzyme layer is positioned on the working electrode of the flexible electrode. The enzyme layer is capable of specifically responding to glucose.

in one embodiment, the enzyme sensor further comprises: an anti-interference layer; the anti-interference layer is positioned on the surfaces of the flexible electrode and the enzyme layer.

in one embodiment, the enzyme sensor further comprises: a diffusion-suppressing layer; the diffusion inhibiting layer is positioned on the surface of the anti-interference layer.

FIG. 13 is a flow chart of a method of making an enzyme sensor according to an embodiment of the invention. As shown in fig. 13, a method of preparing an enzyme sensor, comprising:

S301: preparing a flexible electrode using the first preparation method of a flexible electrode as described above; alternatively, the flexible electrode is prepared using the second flexible electrode second preparation method as described above.

S302: and modifying the enzyme solution on a working electrode of the flexible electrode to obtain the enzyme sensor.

The modification mode of the enzyme solution comprises dripping or soaking, and the enzyme solution can be obtained by mixing glucose oxidase, bovine serum albumin and glutaraldehyde and then carrying out full crosslinking reaction. The concentration of the glucose oxidase is 5mg/mL to 10 mg/mL; the mass fraction of glutaraldehyde was 0.05%.

in an embodiment, after performing S302, the method further includes: the anti-interference layer solution is modified on the surface of the enzyme sensor to form an anti-interference layer, so that the interference of common substances in a body is eliminated, and the selectivity of the electrode is improved.

the anti-interference layer solution can be modified by dripping or soaking. The anti-interference layer solution is a perfluorosulfonic acid polymer solution or a cellulose acetate solution; the solution concentration of the anti-interference layer solution is 1 to 5 percent. Before the anti-interference layer is formed, the enzyme sensor modified with the enzyme layer can be placed in a refrigerator at 4 ℃ for airing.

In one embodiment, the enzyme sensor preparation method further comprises: the diffusion inhibition layer solution is modified on the surface of the anti-interference layer to form a diffusion inhibition layer, so that the linear range of the electrode in-vivo detection is improved, the loss of enzyme on the electrode can be delayed, and the biocompatibility of the electrode is improved. And then, the enzyme sensor modified with the diffusion inhibition layer can be placed in a drying oven at 37 ℃ to be dried for 1 hour, and the enzyme sensor with good stability and electrochemical response can be obtained.

the diffusion inhibition layer can be modified by dropping coating or soaking. The diffusion inhibition layer solution comprises one or any combination of a cellulose acetate solution, a polyurethane solution, a polyvinyl alcohol solution or a polycarbonate solution; the solution concentration of the diffusion suppressing layer solution is 1% to 5%. Before the diffusion inhibition layer is formed, the enzyme sensor modified with the anti-interference layer can be placed in a refrigerator for airing at 4 ℃.

The specific process of the enzyme sensor preparation method is as follows:

1. preparing a flexible electrode using the first preparation method of a flexible electrode as described above; alternatively, the flexible electrode is prepared using the second flexible electrode second preparation method as described above.

2. mixing glucose oxidase, bovine serum albumin and glutaraldehyde, and then carrying out full cross-linking reaction to obtain an enzyme solution.

3. And modifying the surface of the working electrode of the flexible electrode with an enzyme solution by adopting a modification mode of dripping or soaking. When the counter electrode is a columnar electrode, the enzyme layer is modified mainly by adopting a soaking mode, and meanwhile, the enzyme layer can also be modified by adopting a spraying method.

4. And (3) putting the enzyme sensor modified with the enzyme layer in a refrigerator at 4 ℃ for airing.

5. And modifying the surface of the enzyme sensor by using a perfluorosulfonic acid polymer solution or a cellulose acetate solution as an anti-interference layer solution in a drop coating or soaking modification mode to form the anti-interference layer.

6. and (3) placing the enzyme sensor modified with the anti-interference layer in a refrigerator at 4 ℃ for airing.

7. cellulose acetate is dissolved in acetone or polyurethane is dissolved in a solution of tetrahydrofuran. Or dissolving polycarbonate in a solution of tetrahydrofuran to obtain a diffusion inhibiting layer solution.

8. and modifying the diffusion inhibition layer solution on the surface of the enzyme sensor by adopting a modification mode of dripping or soaking to form a diffusion inhibition layer.

9. and (3) drying the enzyme sensor modified with the diffusion inhibition layer in a drying oven at 37 ℃ for 1 hour.

FIG. 14 is a time-line plot of glucose versus three electrodes of an enzyme sensor in an embodiment of the invention. FIG. 15 is a linear plot of the concentration of glucose versus the three electrodes of the enzyme sensor in one embodiment of the present invention. The abscissa of fig. 14 is time in seconds(s); the ordinate is the current in microamps (nA). The abscissa of fig. 15 is concentration in millimoles per liter (mM); the ordinate is the current in microamps (nA). The method is to apply a constant potential method of a three-electrode system, detect the current change obtained by the catalytic oxidation of glucose on the electrode by applying a certain potential, and convert the current change into the glucose concentration at the moment because the current change and the glucose concentration have a trend of positive correlation. As shown in fig. 14 to 15, the enzyme sensor has a very good electrochemical response current to glucose after addition of glucose, and the current responses to the electrode, the working electrode and the reference electrode are almost the same with good uniformity. The enzyme sensor has a good linear range, and the maximum linear detection concentration of the enzyme sensor can reach 20 mM.

FIG. 16 is a graph of the interference rejection of an enzyme sensor for glucose in one embodiment of the invention. The abscissa of fig. 16 is time in seconds(s); the ordinate is the current in microamps (nA). As shown in FIG. 16, the enzyme sensor has excellent anti-interference ability against 0.1mM uric acid, 0.1mM ascorbic acid, 0.2mM acetaminophen and 0.1mM cysteine which are added in sequence.

FIG. 17 is a graph showing the stability of an enzyme sensor over time in one embodiment of the present invention. The abscissa of fig. 17 is time in hours (h); the ordinate is the current in microamps (nA). As shown in FIG. 17, when the enzyme sensor was placed in a buffer solution containing 5mM of glucose phosphate, the response current of the enzyme sensor remained almost constant during continuous testing for up to 16 hours, indicating that the enzyme sensor according to the example of the present invention had excellent stability during long-term testing.

In conclusion, the enzyme sensor and the preparation method thereof provided by the embodiment of the invention can obtain the enzyme sensor with stability, reliability and consistency, reduce the preparation cost and have important significance for continuous monitoring of blood sugar and dynamic analysis and management of diabetes.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.