▎ 摘　　要

NOVELTY - A medical device comprises a graphene varactor (100) comprising a graphene layer (108a,108b), and a self-assembled monolayer comprising pillararene, substituted pillararene, calixarene, substituted calixarene, peralkylated cyclodextrin, substituted peralkylated cyclodextrin, pyrene, substituted pyrene and/or their derivatives, arranged on an outer surface of the graphene layer through non-covalent interactions between the self-assembled monolayer and pi-electron system of graphene. USE - Medical device is used in detection of analyte (claimed) e.g. volatile organic compound in gaseous sample in early detection of diseases including cancer, cardiac disease, infection, multiple sclerosis, Alzheimer's disease and Parkinson's disease. ADVANTAGE - The stable medical device enables detection of analyte e.g. volatile organic compound in gaseous sample with high sensitivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) modification (A) of surface of graphene, which involves forming the self-assembled monolayer arranged on outer surface of graphene layer through non-covalent interactions between the self-assembled monolayer and pi-electron system of graphene, and quantifying an extent of surface coverage of the self-assembled monolayer using contact angle goniometry, Raman spectroscopy, or X-ray photoelectron spectroscopy; and (2) detection (B) of analyte, which involves collecting a gaseous sample, and contacting the gaseous sample with graphene varactors. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic perspective view of the graphene varactor. Graphene varactor (100) Gate electrode (104) Gate electrode fingers (106a-106h) Graphene layers (108a,108b) Contact electrode (110)