Electrochemical sensor and application thereof in glucose detection

Abstract

The invention discloses an electrochemical sensor and application thereof in glucose detection. The electrochemical sensor comprises a working electrode, a counter electrode, a reference electrode and a sacrificial electrode; a working electrode region, a counter electrode region, a reference electrode region and a sacrificial electrode region are arranged on a substrate material of the electrochemical sensor; corresponding electrodes are directly manufactured in corresponding areas through a laser-induced graphene technology; a sensing material is fixedly carried in the working electrode area; the sacrificial material is fixedly loaded in the sacrificial electrode region; a reference electrode material is immobilized in the reference electrode area; and the working electrode area and / or the counter electrode area are / is hollowed-out.

Description

Technical Field

[0001] The present application relates to an electrochemical sensor and its application in detecting glucose, belonging to the field of electrochemical sensors. Background Art

[0002] Quantitative detection of glucose in body fluids provides important data support for monitoring diabetes. Enzyme-based glucose sensors are sensors based on glucose oxidase or glucose dehydrogenase. The detection data is easily affected by temperature, humidity and pH values, and the shelf life is short. Except for a few non-enzyme glucose electrochemical sensors that can be detected at neutral pH (Biosensors and Bioelectronics, 2020 (165): 112331), most of them need to be detected in 0.1-0.5M NaOH solution (RSC Advances, 2016 (6), 84893), so it is difficult to be directly used for glucose concentration detection in body fluids.

[0003] Studies have shown that alkali can be produced by electrolyzing water to produce a local alkaline environment in the sensor detection area (CN201910541655.2 and CN202110100231.X). Zhu et al. used gold electrodes (ACS Sensors, 2018 (3): 1135-1141) and screen-printed electrodes (Analytical Chemistry, 2019 (91), 10764-10771) to electrolyze water to produce alkali, which can realize the detection of glucose in sweat. Both of the above methods are to electrolyze water to produce alkali in a solid-liquid two-phase system. The hydrogen produced by electrolysis cannot escape from the solution in time and will be adsorbed on the surface of the working electrode, affecting the repeatability of the detection area. Summary of the invention

[0004] In order to improve the defects of the prior art, the present invention provides an enzyme-free glucose electrochemical sensor platform, which has the advantages that the preparation of hollow electrodes can be achieved through laser-induced graphene technology; the constructed gas-liquid-solid three-phase interface is conducive to the timely escape of hydrogen generated by electrolysis into the gas phase, thereby ensuring the repeatability of the working electrode surface for detection; the production method is simple and suitable for mass production, providing a detection platform for the production of enzyme-free glucose electrochemical sensors.

[0005] According to one aspect of the present application, there is provided an electrochemical sensor, the electrochemical sensor comprising a working electrode, a counter electrode, a reference electrode and a sacrificial electrode;

[0006] The base material of the electrochemical sensor is provided with a working electrode area, a counter electrode area, a reference electrode area and a sacrificial electrode area;

[0007] Directly fabricate corresponding electrodes in corresponding areas through laser-induced graphene technology;

[0008] In laser-induced graphene technology, the water contact angle of the induced graphene layer is less than 90°;

[0009] The sensing material is immobilized in the working electrode region;

[0010] The sacrificial material is fixed on the sacrificial electrode area;

[0011] The reference electrode material is immobilized in the reference electrode region;

[0012] The working electrode area and / or the counter electrode area are hollowed out.

[0013] The base material is selected from polymer, paper base, cotton fabric;

[0014] The polymer is selected from at least one of polyimide, polyetheretherketone, polyetherimide and polyethersulfone.

[0015] The sensing material is selected from noble metal nanomaterials and / or transition metal nanomaterials;

[0016] The sacrificial material is selected from silver nanomaterials and / or gold nanomaterials;

[0017] The reference electrode material is selected from silver / silver chloride nanomaterials, sodium chloride, potassium chloride, and porous polymers;

[0018] The porous polymer is selected from polyvinyl butyral (PVB) and / or polyvinyl alcohol (PVA).

[0019] The diameter of the hollow hole is 0.1-1 mm.

[0020] According to another aspect of the present application, a method for detecting glucose is provided, using the above-mentioned electrochemical sensor;

[0021] The following steps are involved:

[0022] The liquid to be tested is dripped onto the surface of the electrochemical sensor, and in a loop consisting of a counter electrode, a sacrificial electrode and a reference electrode or a working electrode, a voltage is applied to the counter electrode or the working electrode to electrolyze water in situ on the surface to produce alkali; in a loop consisting of the working electrode, the counter electrode and the reference electrode, the concentration of glucose is detected by a chronoamperometry; in a loop consisting of the sacrificial electrode, the counter electrode and the reference electrode, a voltage is applied to the sacrificial electrode to electrolyze oxides on the surface.

[0023] The volume of the liquid to be tested is less than or equal to 30 μL.

[0024] Compared with the prior art, the enzyme-free glucose electrochemical sensor platform in the method of the present invention has the following advantages:

[0025] 1. The hollowed-out electrode in the method of the present invention can provide a gas-liquid-solid three-phase interface, which is conducive to the timely escape of hydrogen generated by electrolysis into the gas phase, thereby ensuring the repeatability of the working electrode surface for detection.

[0026] 2. The enzyme-free glucose electrochemical sensor platform in the method of the present invention can electrolyze water to produce alkali in situ, solving the problem of difficulty in directly detecting glucose in body fluids.

[0027] 3. In the method of the present invention, the electrode can be directly written onto the substrate material by laser-induced graphene technology. The manufacturing method is simple and suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the electrode pattern of the enzyme-free glucose electrochemical sensor platform in Example 1 of the present application; wherein, 1 is a counter electrode, 2 is a working electrode, 3 is a sacrificial electrode, and 4 is a reference electrode. DETAILED DESCRIPTION

[0029] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0030] Example 1

[0031] An enzyme-free glucose electrochemical sensor platform includes a counter electrode, a working electrode, a sacrificial electrode and a reference electrode. The counter electrode region includes a circular through hole with a diameter of 0.5 mm. A laser engraver with an emission wavelength of 350 nm is used to directly write a specified pattern on a 125 μm thick polyimide film (see attached Figure 1 ).

[0032] Saturated mercuric chloride was used as the reference electrode, platinum wire was used as the counter electrode, the laser-induced graphene working electrode was used as the working electrode, and the electrolyte was 5g / L chloroauric acid and 0.5M sulfuric acid. A voltage of -1.0V was applied to the working electrode for 60s to obtain a gold nanoparticle-modified working electrode. Silver nanoparticles were screen-printed on the surface of the sacrificial electrode. Silver / silver chloride nanoparticles were screen-printed on the surface of the reference electrode, and then sealed with a polyvinyl butyral / sodium chloride / methanol (79.1mg / 50mg / 1mL) solution.

[0033] Glucose detection was achieved by multi-step potentiometric method. 30 μL of a mixed solution of 0.1 M sodium chloride and 10 mM glucose was dripped onto the surface of the electrochemical sensor to ensure that the solution completely soaked the four electrodes. In the first step, in the electrical circuit consisting of the hollow counter electrode, sacrificial electrode and reference electrode, a voltage of -2.5 V was applied to the counter electrode and electrolysis was performed for 30 seconds; in the second step, in the electrical circuit consisting of the gold working electrode, the hollow counter electrode and the reference electrode, the concentration of glucose was detected by chronoamperometry with a voltage of 0.08 V and a detection time of 20 seconds; in the third step, in the electrical circuit consisting of the hollow counter electrode, sacrificial electrode and reference electrode, 2.0 V was applied to the sacrificial electrode and the electrolysis time was 4 seconds. The current signal of 10 mM glucose detected by chronoamperometry was 100.9 μA.

[0034] Example 2

[0035] An enzyme-free glucose electrochemical sensor platform is as described in Example 1, except that: a 0.8 mm circular through hole is hollowed out on the surface of the working electrode, and a laser engraver with an emission wavelength of 10.6 μm is used to directly write on a 125 μm thick polyimide film.

[0036] Glucose detection was achieved through multi-step potentiometry. In the first step, in the circuit composed of the hollow working electrode, sacrificial electrode and reference electrode, a voltage of -2.0V was applied to the working electrode and electrolysis was performed for 20s; in the second step, in the electrical circuit composed of the hollow working electrode, counter electrode and reference electrode, the concentration of glucose was detected by chronoamperometry, with a voltage of 0.24V and a detection time of 20s; in the third step, in the electrical circuit composed of the counter electrode, sacrificial electrode and reference electrode, 2.0V was applied to the sacrificial electrode and the electrolysis time was 4s. The current signal of 10μM glucose detected by chronoamperometry was 98.5μA.

[0037] Example 3

[0038] An enzyme-free glucose electrochemical sensor platform is as described in Example 1, except that: Cu-MOF material is dripped onto the surface of the working electrode prepared by laser-induced graphene, and then sealed with 1 μL of 0.1% Nafion solution.

[0039] Example 4

[0040] An enzyme-free glucose electrochemical sensor platform is as described in Example 1, except that the substrate material of the laser-induced graphene is Whatman No.41 filter paper.

[0041] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An electrochemical sensor, characterized in that The electrochemical sensor comprises a working electrode, a counter electrode, a reference electrode and a sacrificial electrode; The substrate material of the electrochemical sensor is provided with a working electrode area, a counter electrode area, a reference electrode area and a sacrificial electrode area; Directly fabricate corresponding electrodes in corresponding areas through laser-induced graphene; The sensing material is immobilized in the working electrode region; The sacrificial material is fixed on the sacrificial electrode area; The reference electrode material is immobilized in the reference electrode region; The working electrode area and / or the counter electrode area are hollowed out.

2. The electrochemical sensor according to claim 1, characterized in that The base material is selected from polymer, paper base, cotton fabric; The polymer is selected from at least one of polyimide, polyetheretherketone, polyetherimide and polyethersulfone.

3. The electrochemical sensor according to claim 1, characterized in that The sensing material is selected from noble metal nanomaterials and / or transition metal nanomaterials; The sacrificial material is selected from silver nanomaterials and / or gold nanomaterials; The reference electrode material is selected from silver / silver chloride nanomaterials, sodium chloride, potassium chloride, and porous polymers; The porous polymer is selected from polyvinyl butyral and / or polyvinyl alcohol.

4. The electrochemical sensor according to claim 1, characterized in that The diameter of the hollow hole is 0.1-1 mm.

5. A method for detecting glucose, characterized in that: An electrochemical sensor according to any one of claims 1 to 4; The following steps are involved: The liquid to be tested is dripped onto the surface of the electrochemical sensor, and in a loop consisting of a counter electrode, a sacrificial electrode and a reference electrode or a working electrode, a voltage is applied to the counter electrode or the working electrode to electrolyze water in situ on the surface to produce alkali; in a loop consisting of the working electrode, the counter electrode and the reference electrode, the concentration of glucose is detected by a chronoamperometry; in a loop consisting of the sacrificial electrode, the counter electrode and the reference electrode, a voltage is applied to the sacrificial electrode to electrolyze oxides on the surface.

6. The method according to claim 5, characterized in that The volume of the liquid to be tested is less than or equal to 30 μL.

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