Electrochemical sensor electrode surface nano-material modification method and sensor

[0031] The present invention will be further described below in conjunction with the drawings and embodiments.

[0032] It should be pointed out that the following detailed descriptions are all illustrative and are intended to provide further explanations for the application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0033] It should be noted that the terms used here are only for describing specific implementations, and are not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and/or "including" are used in this specification, they indicate There are features, steps, operations, devices, components, and/or combinations thereof.

[0034] In the present invention, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", etc. indicate The azimuth or position relationship is based on the azimuth or position relationship shown in the drawings, and is only a relationship term determined to facilitate the description of the structural relationship of each component or element of the present invention. It does not specifically refer to any component or element in the present invention and cannot be understood as a reference to the present invention. Limitations of the invention.

[0035] In the present invention, terms such as "fixed connection", "connected", "connected", etc. should be understood in a broad sense, indicating that it can be a fixed connection, an integral connection or a detachable connection; it can be directly connected, or through an intermediate connection. The medium is indirectly connected. For the relevant scientific research or technical personnel in the field, the specific meaning of the above terms in the present invention can be determined according to the specific situation, and it should not be understood as a limitation of the present invention.

[0036] Due to the low concentration of the lung cancer protein and polypeptide small molecules to be tested, the detection is difficult. This embodiment plans to adopt the carbon paper electrode surface nanocomposite material modification technology to improve detection sensitivity and specificity, and the surface of the nano-sensitive membrane is easy to immobilize antibodies.

[0037] Through physical adsorption and chemical cross-linking methods, electronic mediators, nanomaterials and various antibodies are fixed on the surface of the carbon sensor working electrode to achieve specific capture of multiple tumor markers and biological signal amplification to improve detection sensitivity and immediacy.

[0038] A method for modifying nanocomposite materials on a carbon working electrode. First, carbon paper is used as the working electrode substrate;

[0039] Subsequently, the gold nano/thionine/graphene nano composite sensitive film was modified on the surface of the working electrode by physical adsorption and chemical cross-linking;

[0040] Finally, the specific antibody is fixed on the biosensitive membrane, and the cancer antigen to be detected is combined with it, and the antigen concentration is proportional to the reduction of the reaction current to achieve the purpose of antigen detection.

[0041] The nanocomposite material is modified on the surface of the sensor (the surface of the working electrode), combined with the differential pulse voltammetry that reduces the background current, and can be used for high-sensitivity and specific detection of trace antigens, proteins, and peptide molecules.

[0042] Graphene oxide modified on the carbon working electrode;

[0043] The polythionine is adsorbed on the surface of graphene oxide;

[0044] The gold nanoparticles react with the amine groups on the reduced graphene oxide, and the polythionine also adsorbs the negatively charged gold nanoparticles, so that the gold nanoparticles are fixed on the electrode surface;

[0045] Put the processed carbon electrode into a certain concentration of K 3 Fe(CN) 6 The surface of the carbon electrode is polished in an aqueous solution with supporting electrolyte. The surface of the carbon electrode is physically adsorbed and chemically cross-linked to immobilize electronic mediators, nanocomposites and different antibodies on the surface of the carbon working electrode of the sensor, using the interaction between gold nanoparticles and the amino groups of the antibodies , Fix the specific antibody on the surface of the nanocomposite material through the self-assembly technology, and fix it effectively.

[0046] When the antigen to be detected drops on the surface of the biosensor, the high-specific combination of the antibody and the antigen of the test object produces a change in the electric field, which hinders the diffusion of the electroactive substance to the electrode surface, and the detected current is reduced;

[0047] Use the differential voltammetry pulse method of current suppression to detect the weak reaction current of antibody and antigen binding;

[0048] Using the principle that the antigen concentration is proportional to the reduction of the reaction current, the antigen concentration is obtained by conversion.

[0049] Such as figure 1 As shown, the nanocomposite material carrier is a carbon paper working electrode (using a three-electrode working system: working electrode, counter electrode and reference electrode), which is realized by surface modification of the carbon working electrode;

[0050] The present invention uses a low-cost carbon working electrode as a sensor substrate, and performs nano-modification and antibody immobilization on its surface;

[0051] Make full use of the nano-effects of graphene-thionine-nano-gold electroactive composite materials;

[0052] Polythionine has good electrochemical reversibility, stability and fast electron transfer ability. It is a good electronic mediator and contains two -NH2 groups. It can adsorb negatively charged nanometers through covalent bonding and electrostatic interaction. Gold particles to form a nano-gold monolayer;

[0053] Thionine is used as the electronic mediator. Thionine has a benzene ring structure and generates a π-π stacking interaction with graphene. By virtue of this interaction, thionine is adsorbed to the surface of reduced graphene oxide and fixed on Carbon electrode surface;

[0054] Graphene has unique physical and chemical properties such as monolithic properties, high conductivity, large specific surface area, anti-toxicity and good electron transfer kinetics, and is widely used in electrochemical sensing and biological sensing;

[0055] Preparation of synthetic gold nanoparticles. Nanoparticles are fixed by reacting with the amine group on the reduced graphene oxide to form a complex. The gold nanoparticles are used to immobilize specific antibodies. At the same time, the gold nanoparticles have good electrical conductivity and can also play current The effect of magnification;

[0056] The synthesized nanocomposite material is modified on the surface of the electrode to increase the surface-to-volume ratio and electron transfer capacity, and amplify the signal to improve the detection sensitivity;

[0057] The working electrode used is a carbon electrode. After surface treatment, a gold nano/thionine/graphene nanocomposite film is formed on the working electrode, and then an antibody is added, and the antibody is fixed on the working electrode by the interaction between the gold nano and the amino group of the protein .

[0058] In summary, the present invention directionally modifies nanocomposite materials and electroactive substances by electrodeposition technology on the surface of the sensing electrode, and then fixes the antibody on the surface of the nanomaterial by self-assembly technology, and generates an electric field through the highly specific combination of the antibody and the antigen of the test object. The change hinders the diffusion of the electroactive substance to the surface of the electrode, so that the detected current is reduced, so that the concentration of the antigen to be tested is inversely proportional to the magnitude of the detected current.

[0059] The foregoing descriptions are only preferred embodiments of the application, and are not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of this application shall be included in the protection scope of this application.

[0060] Although the specific embodiments of the present invention are described above with reference to the accompanying drawings, they do not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solutions of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.