▎ 摘　　要

NOVELTY - Biosensor identification element comprises high-purity silicon carbide as a substrate and a single molecular layer graphene structure on the substrate. USE - The biosensor identification element and the biosensor constructed using the biosensor identification element are useful for detecting nucleic acid (claimed). ADVANTAGE - The detection method (M2) does not require DNA labeling. The biosensor identification element has high sensitivity for detection of nucleic acids, simple preparation and operation, good stability, and rapid response speed. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) method (M1) for preparing the biosensor identification element, which involves (a) preparing high-purity silicon carbide (SiC) source material, (b) preparing micropipe-free SiC crystal, (c) cutting and preparing 4 hydrogen (H)-SiC crystal substrate, (d) removing surface scratches by hydrogen etching, and (e) preparing molecular layer graphene on the surface of the hydrogen-etched SiC substrate; and (2) method (M2) for detecting nucleic acid using a biosensor constructed using the biosensor identification element involves (a) designing a probe according to the nucleic acid to be detected, where the probe sequence is the reverse complementary DNA sequence of the nucleic acid to be detected in which cytosine, adenine or guanine base is added at the 5' end and an amino base modification is performed at the 5' end, (b) respectively dissolving the probe sequence and the amplified nucleic acid to be detected in phosphate-buffered saline (PBS) solution, heating the mixed solution, where the mixed solution is equimolar, slowly cooling to room temperature and annealing to form a double stranded DNA, where the double stranded DNA is covalently coupled to the surface of the identification element, (c) carrying out functional treatment on the biosensor identification element, fixing a probe and sealing the surface of the biosensor identification element, where the functional processing of the biosensor identification element involves functionalizing the surface of the biosensor identification element through diazotization reaction, and (d) controlling surface temperature of the biosensor identification element, enabling the biosensor to identify the probe on the surface of the component to form a double strand with the nucleic acid to be detected, or to dissociate the formed double strand of the nucleic acid, determining the current signal changes in the biosensor during the process, analyzing the data obtained using R language and determining the concentration and mutation of the nucleic acid to be detected.