▎ 摘　　要

NOVELTY - Nucleic acid biosensor comprises silver/silver chloride as a gate, indium tin oxide as a source and a drain, graphene as a conductive layer and glass as a substrate. USE - The biosensor is useful for RNA detection. ADVANTAGE - The biosensor uses DNA and PNA as probes to detect RNA, and the results show that: (a) PNA as a probe has a significant sensitivity improvement compared to DNA, and (b) when multi-layer graphene is used as the conductive layer, it has better detection effect than single-layer graphene, and helps shorten the time required for incubation. The detection system significantly reduces the time required for incubation, improves detection sensitivity, and has significant technical effects and promotion significance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing the nucleic acid biosensor, involving preparing graphene as a conductive layer by chemical vapor deposition, and transferring the graphene to a glass substrate by a wet transfer method, providing indium tin oxide thin film layers on both sides of graphene as a source and a drain, providing a sample cell on the glass substrate, and inserting the gate material into the sample cell to form the nucleic acid biosensor, where the chemical vapor deposition method uses copper as a substrate and ethanol as a carbon source; (2) a use of a peptide nucleic acid (PNA) probe in the nucleic acid biosensor; and (3) an RNA detection method, involves using the nucleic acid biosensor and a PNA probe for detection.