Cortisol sensor based on three-dimensional porous graphene composite electro-catalysis sensing interface as well as preparation method and application of cortisol sensor

Abstract

The invention discloses a sensor based on a three-dimensional porous graphene composite electro-catalysis sensing interface and a preparation method and application thereof, and belongs to the field of sensors. The composite electro-catalysis sensing interface comprises a laser-induced graphene electrode and cobaltous oxide nanoparticles; the cobaltous oxide nanoparticles are modified at the interface of the laser-induced graphene electrode. The cortisol sensor is a three-electrode electrochemical sensor prepared based on a laser-induced graphene technology, a recognition element of the cortisol sensor is a nano material with catalytic activity, sensing recognition is performed based on an electrochemical catalysis mechanism, incubation binding and redox probes are not needed, the preparation process is simple, response is faster, and rapid real-time analysis of cortisol is facilitated.

Description

Technical Field

[0001] The present application relates to a sensor based on a three-dimensional porous graphene composite electrocatalytic sensing interface and a preparation method and application thereof, and belongs to the field of sensors. Background Art

[0002] Cortisol is an important biological stress marker with the characteristics of low concentration and rapid change. Therefore, it has high requirements for analytical sensitivity and analysis rate. The mainstream detection methods of cortisol molecules, such as liquid chromatography-tandem mass spectrometry and enzyme-linked immunosorbent assay strips, have long test time, high cost, and relatively complex detection process, which cannot meet the needs of rapid and real-time detection. The electrochemical method has the advantages of high sensitivity, strong specificity, low cost, and fast response, but the electrochemical activity of cortisol molecules is extremely weak. Existing research mainly constructs its immunosensor based on biological antibodies or constructs bionic immunosensors based on molecular imprinting bionic recognition elements. The preparation process is complicated and costly, and a certain incubation binding time and analysis time are required, and there is a certain hysteresis. Therefore, it is urgent to construct an electrochemical sensor with a simple preparation process, low cost, and based on a non-immune recognition mechanism to establish a rapid real-time detection method for cortisol.

[0003] Patent CN118795002A discloses a sensor for detecting cortisol in sweat based on laser-induced graphene. The organic electrochemical transistor is prepared based on laser-induced graphene technology. Its recognition element is a molecular imprinted polymer. The sensing and recognition is based on the mechanism of specific binding. The preparation process is complicated and the binding conditions are relatively strict. After incubation and binding, analysis and detection are carried out with the help of redox probes, which is not conducive to real-time analysis and detection of cortisol. Summary of the invention

[0004] Based on this, the present application provides a three-dimensional porous graphene composite electrocatalytic sensing interface and a cortisol sensor. The cortisol sensor is based on a composite electrocatalytic sensing interface constructed of laser-induced graphene (LIG) and cobaltous oxide nanoparticles (CoO NPs), which can measure the electrochemical catalytic signal of cortisol and is used for electrochemical analysis of cortisol.

[0005] According to a first aspect of the present application, a composite electrocatalytic sensing interface based on three-dimensional porous graphene is provided.

[0006] A composite electrocatalytic sensing interface based on three-dimensional porous graphene, wherein the composite electrocatalytic sensing interface comprises a laser-induced graphene electrode and cobaltous oxide nanoparticles;

[0007] The cobaltous oxide nanoparticles are modified at the interface of the laser induced graphene electrode.

[0008] According to the second aspect of the present application, a method for preparing a composite electrocatalytic sensing interface based on three-dimensional porous graphene is provided. CoO NPs are modified at the interface of three-dimensional porous graphene such as laser-induced graphene, and the preparation process is simple, the cost is low, the response is higher, and the sensitivity is higher.

[0009] The method for preparing the composite electrocatalytic sensing interface described above comprises:

[0010] S1 obtains LIG electrode;

[0011] S2 dissolving the cobaltous oxide nanoparticles in water to obtain a cobaltous oxide nanoparticle dispersion;

[0012] S3: dripping cobalt oxide nanoparticle dispersion onto the working electrode surface of the LIG electrode and drying the mixture to obtain the three-dimensional porous graphene-based composite electrocatalytic sensing interface.

[0013] Optionally, the step S1 includes:

[0014] A laser-induced graphene electrode is prepared on the surface of a carbon-containing substrate material, impurities are removed, the material is blown dry, a reference electrode position is coated with an Ag / AgCl slurry, the material is dried to form a reference electrode, and the material is insulated and packaged to obtain a LIG electrode.

[0015] Optionally, the carbon-containing substrate material is selected from at least one of a polyimide film, a phenolic resin film, a cross-linked polystyrene, an epoxy resin and paper.

[0016] Optionally, step S2 includes:

[0017] The cobaltous oxide nanoparticles are dissolved in water, vortexed and ultrasonicated to make the cobaltous oxide nanoparticles evenly dispersed to obtain a cobaltous oxide nanoparticle dispersion.

[0018] Optionally, in step S2, the concentration of the cobaltous oxide nanoparticle dispersion is 0.5-3.0 mg / mL.

[0019] Optionally, the concentration of the cobaltous oxide nanoparticle dispersion is selected from any value of 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, or any range therebetween.

[0020] According to a third aspect of the present application, a cortisol sensor is provided.

[0021] A cortisol sensor, comprising a LIG electrode and a LIG / CoO electrode;

[0022] The LIG / CoO electrode includes a composite electrocatalytic sensing interface;

[0023] The composite electrocatalytic sensing interface is selected from the composite electrocatalytic sensing interface described above.

[0024] According to a fourth aspect of the present application, an application of a cortisol sensor is provided.

[0025] Application of the above-mentioned cortisol sensor in cortisol detection.

[0026] Optionally, for electrochemical analysis of cortisol.

[0027] The cortisol sensor is a three-electrode electrochemical sensor prepared based on laser-induced graphene technology. Its recognition element is a catalytically active nanomaterial. It performs sensing and recognition based on an electrochemical catalytic mechanism. It does not require incubation and combination with redox probes. The preparation process is simple and the response is faster, which facilitates rapid real-time analysis of cortisol.

[0028] The beneficial effects of this application include:

[0029] The three-dimensional porous graphene composite electrocatalytic sensing interface and cortisol sensor provided in the present application do not require an incubation binding step, have high timeliness, improve the detection rate, and can realize real-time analysis; the preparation process is simple, can be prepared in batches, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 These are electron microscope morphology images of the LIG / CoO composite electrocatalytic sensing interface of Example 1. The scale of Figure A is 200 μm, and the scale of Figure B is 200 nm.

[0031] Figure 2 The electrochemical behavior of the LIG / CoO composite electrocatalytic sensing interface and the LIG sensing interface in Example 1 to cortisol.

[0032] Figure 3 The LIG / CoO composite electrocatalytic sensing interface of Example 1 was used to detect cortisol standard solutions of different concentrations (5 nM, 10 nM, 20 nM, 50 nM, 100 nM) using the CV method, and the oxidation peak current corresponding to the +0.25 V position was recorded.

[0033] Figure 4 Based on Figure 3 The linear relationship curve is drawn. DETAILED DESCRIPTION

[0034] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise specified, the raw materials and catalysts in the examples of this application were purchased through commercial channels.

[0036] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.

[0037] CoO NPs were purchased from Hebei Hangba Metal Materials Co., Ltd.

[0038] In the embodiment, the interface morphology is analyzed using a scanning electron microscope (SEM), and the instrument model is Hitachi SU8010.

[0039] In the embodiment, laser induced graphene is prepared using a laser engraving machine from Tianjin Jiayin Nanotechnology Co., Ltd.

[0040] In the examples, electrochemical analysis was performed using the PalmSens4 electrochemical workstation produced by Radiometer.

[0041] Example 1

[0042] Step 1: Import the electrode pattern into a computer connected to a laser engraver, set the laser power to 1300 mW, the scanning rate to 1.0 cm / s, start the program, and prepare the laser-induced graphene electrode on the surface of the polyimide film.

[0043] Step 2: Use pure water to clean the electrode surface to remove impurities, blow dry with nitrogen, use Ag / AgCl slurry to coat the reference electrode position, and dry in a 70°C oven for 30 minutes to form a reference electrode. Use polyimide tape for insulation packaging to complete the preparation of the LIG electrode.

[0044] Step 3: Weigh 1.0 mg of CoO NPs into a centrifuge tube, add 1 mL of pure water, vortex for 2 min, and place in a high-power ultrasonic cleaner for 2 h to evenly disperse the CoO NPs to obtain a CoO NPs material dispersion.

[0045] Step 4: Add 10 μL of CoO NPs dispersion onto the working electrode surface of the LIG electrode and dry it in an oven at 50 °C to obtain a LIG / CoO composite electrocatalytic sensing interface.

[0046] Example 2

[0047] The operation was the same as in Example 1, except that in step 3, the amount of CoO NPs used was 0.5 mg.

[0048] Example 3

[0049] The operation was the same as in Example 1, except that in step 3, the amount of CoO NPs used was 3.0 mg.

[0050] Characterization analysis

[0051] The morphology of the LIG / CoO composite electrocatalytic sensor interface prepared in Examples 1 to 3 was analyzed. Example 1 was used as a typical example. Figure 1 As shown, the scale of Figure A is 200μm, and the scale of Figure B is 200nm. It can be seen that CoNPs have been uniformly deposited at the LIG interface.

[0052] Electrochemical analysis

[0053] The LIG / CoO composite electrocatalytic sensing interfaces prepared in the above Examples 1 to 3 were subjected to electrochemical analysis, with Example 1 being used as a typical example.

[0054] The LIG electrode and LIG / CoO electrode were connected to the electrochemical workstation, and the cortisol solution was analyzed and detected by cyclic voltammetry (scanning potential of -1.5V to +0.5V, scanning rate of 0.05V / s). The electrochemical behavior of the LIG / CoO composite electrocatalytic sensing interface and the LIG sensing interface for cortisol was compared ( Figure 2 ), the results showed that the composite electrocatalytic sensing interface had a higher electrochemical catalytic response to cortisol.

[0055] Under the condition of phosphate electrolyte pH 7.4, the CV method was used to detect the cortisol standard solutions of different concentrations (5nM, 10nM, 20nM, 50nM, 100nM), and the oxidation peak current corresponding to the +0.25V position was recorded ( Figure 3 ) and draw a linear relationship curve ( Figure 4 ), it can be seen that in the range of 5nM to 100nM, the sensing interface has a linear relationship with cortisol, R 2 =0.9939.

[0056] 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. A composite electrocatalytic sensing interface based on three-dimensional porous graphene, characterized in that: The composite electrocatalytic sensing interface includes a laser-induced graphene electrode and cobaltous oxide nanoparticles; The cobaltous oxide nanoparticles are modified at the interface of the laser induced graphene electrode.

2. The method for preparing the composite electrocatalytic sensing interface according to claim 1, characterized in that: include: S1 obtains LIG electrode; S2 dissolving the cobaltous oxide nanoparticles in water to obtain a cobaltous oxide nanoparticle dispersion; S3: dripping cobalt oxide nanoparticle dispersion onto the working electrode surface of the LIG electrode and drying the mixture to obtain the three-dimensional porous graphene-based composite electrocatalytic sensing interface.

3. The preparation method according to claim 2, characterized in that: The step S1 comprises: A laser-induced graphene electrode is prepared on the surface of an aromatic carbon-containing substrate material, impurities are removed, the electrode is blown dry, a reference electrode position is coated with an Ag / AgCl slurry, the electrode is dried, a reference electrode is formed, and an insulated package is performed to obtain a LIG electrode.

4. The preparation method according to claim 3, characterized in that: The carbon-containing base material is selected from at least one of polyimide film, phenolic resin film, cross-linked polystyrene, epoxy resin and paper.

5. The preparation method according to claim 2, characterized in that: The step S2 comprises: The cobaltous oxide nanoparticles are dissolved in water, vortexed and ultrasonicated to make the cobaltous oxide nanoparticles evenly dispersed to obtain a cobaltous oxide nanoparticle dispersion.

6. The preparation method according to claim 2, characterized in that: In the step S2, the concentration of the cobaltous oxide nanoparticle dispersion is 0.5-3.0 mg / mL.

7. A cortisol sensor, characterized in that: The cortisol sensor comprises a LIG electrode and a LIG / CoO electrode; The LIG / CoO electrode includes a composite electrocatalytic sensing interface; The composite electrocatalytic sensing interface is selected from the composite electrocatalytic sensing interface described in claim 1.

8. Use of the cortisol sensor according to claim 7 in cortisol detection.

9. The use according to claim 8, characterized in that: For electrochemical analysis of cortisol.

Images