A kind of nanocomposite electrode material for rapid high-sensitivity detection of glucose

Abstract

The application belongs to the technical field of functional composite materials, and discloses a kind of nanometer composite electrode materials for rapid high-sensitivity detection of glucose.First, silver nanowires are physically adsorbed to a glassy carbon electrode;Then, according to the principle of positive and negative charges attracting each other, gold nanoclusters are stably adsorbed on the surface of cationic polymer polyethylene glycol-poly-L-lysine micelles, obtaining a gold nanocluster-polyethylene glycol-poly-L-lysine composite;The composite is physically adsorbed to the glassy carbon electrode containing silver nanowires to prepare a silver nanowire-gold nanocluster-polyethylene glycol-poly-L-lysine nanocomposite material.This new nanocomposite material can achieve high-sensitivity rapid detection of glucose in solution, and the method is simple and easy to operate, with good prospects for analysis and detection applications.

Description

TECHNICAL FIELD

[0001] The present application relates to a new type of nanocomposite material applied to glucose detection, belonging to the technical field of functional composite materials. BACKGROUND

[0002] The content of glucose in the human body is an important indicator reflecting the blood glucose concentration of diabetic patients, so rapid, accurate and stable real-time monitoring of the content of glucose in the human body is an important means to understand the progress of diabetes. Electrochemical technology is widely used in glucose detection due to its rapid response, simple operation and high accuracy.

[0003] Compared with the electrochemical enzyme glucose sensor which is easily affected by environmental temperature, humidity and pH value, the electrochemical enzyme-free glucose sensor is favored by more researchers. Among them, noble metal, non-noble metal transition metal, conductive polymer and other nanomaterials are widely used in the synthesis of enzyme-free glucose electrode materials. Compared with pure metal nanomaterials, composite materials composed of one or more electrochemically active elements have unique synergistic catalytic effect, so composite materials containing different metal elements can be used as electrode materials to improve their sensing performance.

[0004] Therefore, it is necessary to explore a new type of nanocomposite electrode material integrating noble metal nanomaterials (silver nanowires, gold nanoclusters) and conductive polymers (polyethylene glycol-poly-L-lysine) and use it for electrochemical analysis and detection of glucose, so as to provide more theoretical basis and support for the prevention and diagnosis of diabetes, and there is no related report at present. SUMMARY

[0005] In view of the deficiencies of the existing detection technology, the present application aims to provide a nanocomposite electrode material which is applied to enzyme-free glucose electrochemical sensor to realize rapid and high-sensitivity glucose detection.

[0006] In order to achieve the purpose of the present application, the nanocomposite electrode material comprises noble metal silver nanowires, gold nanoclusters and cationic polymer polyethylene glycol-poly-L-lysine with excellent conductivity. First, a glassy carbon electrode containing silver nanowires (Ag) is prepared; then according to the principle that positive and negative charges attract each other, a composite gold nanocluster-polyethylene glycol-poly-L-lysine (Au@PEG-PLL) is prepared; further, the polymer Au@PEG-PLL is physically adsorbed onto the glassy carbon electrode containing silver nanowires to prepare an electrode containing nanocomposite material Ag@Au@PEG-PLL, thereby realizing rapid, real-time and high-sensitivity detection of glucose.

[0007] The specific technical solutions are as follows:

[0008] 1) Preparation of nanomaterials

[0009] a. Using chloroauric acid (HAuCl4) and glutathione (GSH) as raw materials, gold nanoclusters with negative charges on the surface were prepared by hydrothermal synthesis.

[0010] b. According to the principle of positive and negative charges attracting each other, gold nanoclusters were mixed with polyethylene glycol-poly-L-lysine in a mass ratio of 1: (7-22) to prepare nanocomposite Au@PEG-PLL.

[0011] Among them, the cationic polymer PEG-PLL preferably has a molecular weight of 6000-10000, and the molecular weight of the PEG segment is 1000-4000.

[0012] 2) Structure and property characterization of nanocomposite

[0013] Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential instrument, particle size analysis and other characterization methods were used to analyze the morphology, structure, surface charge and particle size of the target molecules.

[0014] 3) Preparation of working electrode containing nanocomposite Ag@Au@PEG-PLL

[0015] a. Prepare a clean glassy carbon electrode as a working electrode.

[0016] b. Physically adsorb silver nanowires onto the glassy carbon electrode and dry at room temperature for standby.

[0017] c. Further physically adsorb the composite Au@PEG-PLL onto the glassy carbon electrode containing silver nanowires to prepare a working electrode containing nanocomposite Ag@Au@PEG-PLL, and dry at room temperature for standby.

[0018] d. Examine the sensitivity of the working electrode by measuring the C-V curve.

[0019] 4) Application of working electrode containing composite Ag@Au@PEG-PLL for glucose detection

[0020] The working electrode containing the composite Ag@Au@PEG-PLL is used for electrochemical analysis and detection of glucose. It is mainly based on the fact that silver nanowires, gold nanoclusters and PEG-PLL all have good electronic conductivity, and silver nanowires and gold nanoclusters have good catalytic performance for glucose. At the same time, the above composite nanomaterials have high specific surface area, good mechanical strength, and synergistic catalytic effect between silver and gold bimetallic, so the above three nanomaterials are assembled together for electrochemical analysis and detection of glucose, which can achieve complementary advantages between materials, improve the sensitivity of detection, and realize rapid and high-sensitivity qualitative or quantitative detection of glucose.

[0021] Compared with the prior art, the present application has the following advantages and effects:

[0022] 1、The electrode material is composed of silver nanowires, gold nanoclusters and cationic polymer PEG-PLL, which is made into a working electrode, and through the action with glucose, rapid and high-sensitivity detection of glucose is realized, and the detection method is simple and easy to operate. 2、The introduction of silver nanowires can effectively improve the conductivity of the electrode material; silver nanowires and gold nanoclusters have synergistic catalytic ability for electrode reaction; cationic polymer PEG-PLL can better adsorb gold nanoclusters with negative charges on the surface, so that the electrode material is more firmly assembled together; and the composite material is not easy to aggregate in the catalytic process, which is beneficial to improve the electron transfer rate and catalytic performance. The electrochemical test results show that the enzyme-free glucose electrochemical sensor of the Ag@Au@PEG-PLL composite material constructed by the method has rapid and high sensitivity. The practical application results show that the glucose sensor has good stability, high sensitivity, strong anti-interference ability, wide detection range and good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a scanning electron micrograph of silver nanowires;

[0024] Figure 2 It is a transmission electron micrograph of gold nanoclusters;

[0025] Figure 3 It is a particle size distribution graph of PEG-PLL;

[0026] Figure 4 It is a scanning electron micrograph of Au@PEG-PLL;

[0027] Figure 5 It is a CV curve graph of the working electrode containing the nanocomposite Ag@Au@PEG-PLL in potassium ferricyanide solution; Figure 6 It is a CV curve graph of the working electrode containing the nanocomposite Ag@Au@PEG-PLL for detecting glucose solution; DETAILED DESCRIPTION

[0028] In order to better illustrate the present application, the following examples are described, which are essentially only exemplary and are not intended to limit the present application.

[0029] Example 1

[0030] First, gold nanoclusters with catalytic function are prepared, which are assembled with polyethylene glycol-poly-L-lysine into a new nanocomposite Au@PEG-PLL. The specific steps are as follows:

[0031] a. The negatively charged fluorescent gold nanoclusters are prepared by a hydrothermal synthesis method using chloroauric acid HAuCl4 and glutathione (GSH) as raw materials.

[0032] b. According to the principle of positive and negative charges attracting each other, the gold nanoclusters Au NCs are mixed with the polymer PEG-PLL at a mass ratio of 1: (7-22) to assemble a new nanocomposite Au@PEG-PLL. The morphology, structure, surface charge and particle size of the electrode material are analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential instrument and particle size analysis, etc. (as shown in Figures 2-4

[0033] Example 2

[0034] Preparation of working electrode

[0035] A clean glassy carbon electrode is selected as the working electrode. First, the glassy carbon electrode is polished with aluminum oxide powder, and then the working electrode, reference electrode and counter electrode are installed according to the specification and placed in a potassium ferricyanide solution. The relevant parameters of the electrochemical workstation are set, and the CV curve of the above working electrode in the potassium ferricyanide solution is tested by using the electrochemical workstation, and the smoothness of the bare electrode is observed. Ensure that the oxidation peak and reduction peak in the CV curve are as close as possible, and the potential difference between the two is less than 110 mV, to ensure that the smoothness of the bare electrode can meet the detection requirements.

[0036] Example 3

[0037] Preliminary modification of working electrode

[0038] a. Preparation of glassy carbon electrode containing Ag nanowires

[0039] The scanning electron microscope image of the Ag nanowires prepared in the laboratory earlier is shown in Figure 1 . Take 10 μL of the silver nanowire solution and drop it onto a clean glassy carbon electrode, and let it dry at room temperature for later use.

[0040] Secondary modification of working electrode

[0041] b. Preparation of Ag@Au@PEG-PLL glassy carbon electrode

[0042] Take 10 μL of the Au@PEG-PLL solution prepared in Example 1 and drop it onto the glassy carbon electrode containing silver nanowires to prepare a glassy carbon electrode containing composite material Ag@Au@PEG-PLL, and let it dry at room temperature for later use.

[0043] Example 4

[0044] Sensitivity test of Ag@Au@PEG-PLL modified glassy carbon electrode

[0045] ​a. The glassy carbon electrode modified with the nanocomposite Ag@Au@PEG-PLL was placed in a potassium ferricyanide solution of a certain concentration, and the CV curve of the system was scanned using an electrochemical workstation to test the sensitivity of the working electrode (as shown in Figure 5 The results showed that, compared with the CV curve of the bare electrode, the electrode modified with Ag@Au@PEG-PLL had obvious redox peaks at 0.18 V and 0.27 V, and the peak current signal was significantly enhanced, indicating that the electrode modified with the nanocomposite had good sensitivity.

[0046] Example 5

[0047] The glassy carbon electrode modified with the nanocomposite Ag@Au@PEG-PLL was used for the detection and analysis of glucose, and the specific steps were as follows:

[0048] a. A PBS solution with a concentration of 0.1 M and a pH of 7.4 was prepared;

[0049] b. Using the above PBS solution, glucose solutions of different concentrations were prepared, such as 0.4 mM, 1 mM, 3 mM, 5 mM, 10 mM, 50 mM, 100 mM, etc.;

[0050] c. The CV curve of the electrode modified with the nanocomposite Ag@Au@PEG-PLL for detecting glucose solutions of different concentrations was tested using an electrochemical workstation (as shown in Figure 6 The results showed that the CV curve of the electrode modified with the nanocomposite Ag@Au@PEG-PLL for detecting glucose solutions had a relatively strong electrochemical signal near the position of 0.16 V, and the signal gradually increased with the increase of the glucose concentration.

Claims

1. A nanocomposite electrode material for glucose detection, characterized in that, It is prepared by the following method: a. Gold nanoclusters were prepared by hydrothermal synthesis using chloroauric acid and glutathione as raw materials; b. Adsorb gold nanoclusters onto the surface of cationic polymer micelle polyethylene glycol-poly-L-lysine PEG-PLL to prepare the nanocomposite Au@PEG-PLL; c. Add the silver nanowire solution dropwise onto the glassy carbon electrode and air dry at room temperature to obtain a glassy carbon electrode containing silver nanowires; d. A solution of the nanocomposite Au@PEG-PLL was dropped onto a glassy carbon electrode containing silver nanowires and dried at room temperature to obtain the nanocomposite electrode material Ag@Au@PEG-PLL.

2. The nanocomposite electrode material as described in claim 1, characterized in that, The cationic polymer PEG-PLL has a molecular weight of 6000-10000, wherein the molecular weight of the PEG segment is 1000-4000.

3. The application of the nanocomposite electrode material as described in claim 1 or 2, characterized in that, It was applied to the detection of glucose.

4. The application of the nanocomposite electrode material as described in claim 3, characterized in that, Electroanalytical chemistry methods are used for qualitative or quantitative analysis and detection of glucose.

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