▎ 摘　　要

NOVELTY - Nano-gold particle/reduction oxidation graphene/graphite-phase carbon nitride composite material comprises reduction oxidation graphene graphite-phase carbon nitride loaded on surface of reduction oxidation graphene and nano-gold particles dispersed between surface of reduction graphene and graphite-phase carbon nitride and pores. USE - Nano-gold particle/reduction oxidation graphene-phase carbon nitride composite material used in detecting DNA methylation (claimed). ADVANTAGE - The nano-gold particle/reduction oxidation graphene-phase carbon nitride composite material forms heterojunction with stable structure, improves stability of electrochemical detection, and has good electrochemical signal response, wide linear response range and low detection characteristics. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. a method for preparing nano-gold particles/reducing oxidation graphene/graphite-phase carbon nitride composite material, which involves: a. mixing oxidized graphene, graphite-phase carbon nitride with water, sequentially ultrasonically stripping, carrying out hydrothermal reaction to obtain reduced oxidation graphene graphite-phase carbon nitride composite; and b. mixing reduced graphene and graphite-phase carbon nitride compound, chloroauric acid, reducing agent and water, and performing reduction reaction to obtain nano-gold particles/reducing oxidized graphene/graphite-phase carbon nitride composite material; 2. a DNA methylation detection probe, which comprises nano-gold particle/reduction oxidation graphene-phase carbon nitride composite material and loaded on gold nanoparticle/reduced graphene oxide/graphite anti-5'-methylcytosine antibody on surface and internal pores of carbon nitride composites; 3. a kit for detecting DNA methylation, which comprises DNA methylation detection probe, DNA probe for modifying sulfydryl 5' end, gold electrode, and sealing agent containing sulfydryl; 4. a method for constructing electrochemical detection DNA methylation immune biological sensor, which involves: a. adding DNA probe dispersion of 5' end modified sulfydryl to surface of gold electrode, performing first step of incubation, washing unbound substance, obtaining gold electrode fixed with DNA probe; b. adding sealing agent containing sulfydryl to surface of gold electrode fixed with DNA probe, performing second step of incubation, washing unbound substance to obtain gold electrode of closed active site; c. adding target DNA sample to be detected to surface of gold electrode of closed active site, performing third step of incubation, washing unbound substance, obtaining gold electrode combined with target DNA; and d. adding DNA methylation detection probe to surface of gold electrode combined with target DNA, performing fourth step of incubation, washing unbound substance to obtain electrochemical detection DNA methylation immune biosensor, where target DNA to be detected is DNA fragment with different methylation degree; and 5. a method for detecting DNA methylation degree based on electrochemical immune biological sensor, which involves: a. constructing electrochemical detection DNA methylation immune biosensor; b. performing electrochemical detection on electrochemical detection DNA methylation immunobiosensor to obtain peak current; c. obtaining methylation degree of target DNA according to peak value current and predetermined standard curve, where standard curve is change curve of methylation degree of peak value current with target DNA.