▎ 摘　　要

(CN212568599-U) NOVELTY - The utility model claims a biological sensor for nucleic acid detection and preparation method and application thereof. non-marking graphene field effect transistor flexible biosensor, comprising a substrate and a PDMS cover plate; the substrate is paved with a single-layer graphene; the single-layer graphene is plated with active/drain electrode; the PDMS cover plate is covered on the single-layer graphene between the source/drain electrodes; the micro-flow channel on the PDMS cover plate is connected with the single-layer graphene; the single-layer graphene surface is modified with a probe bonding material. The utility model uses polylastin and so on to modify the single-layer graphene, the single-layer graphene after functional modification, by electrostatic adsorption, the DNA probe molecule is adsorbed and fixed on the single-layer graphene surface, so as to detect the miRNA. The flexible biosensor of the invention has simple preparation technique, low cost, high sensitivity and low detection limit. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing the biosensor, comprising: (i) growing the single-layer graphene on a surface of a copper sheet substrate, (ii) spin coating a layer of poly(methyl methacrylate) on the copper sheet with the single-layer graphene, (iii) placing spin-coated copper sheet in an etching liquid to prepare a continuous single-layer graphene with a layer of poly(methyl methacrylate), (iv) placing a layer of poly(methyl methacrylate) single-layer graphene on the substrate, (v) removing poly(methyl methacrylate) on the single-layer graphene, (vi) covering a mask plate on the single-layer graphene on the substrate, and plating the source/drain electrode, (vii) covering the polydimethylsiloxane cover plate with the micro-flow channel on the single-layer graphene between source/drain electrodes, (viii) injecting the probe binding material solution into the micro-flow channel and allowing to stand for 8-15 hour, and (9) placing the grid electrode in the micro-flow channel; (2) detecting miRNA based on graphene field effect tube, comprising: (i) injecting DNA probe into micro-flow channel, incubating, and washing to clean, (ii) injecting miRNA to-be-tested into the micro-flow channel, connecting the reference electrode to test the transfer characteristic of the graphene field effect transistor, and (iii) measuring amount of miRNA by variation of electrical characteristics of field effect transistor; and (3) wearable device, comprising the biosensor. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of unmarked graphene field effect transistor flexible biosensor. Polydimethylsiloxane cover plate (1) Micro-flow channel (3) Single-layer graphene (4) Substrate (5)