▎ 摘　　要

NOVELTY - Biosensor comprises a substrate (11), a working electrode (12) arranged on the substrate and a graphene layer, a counter electrode (13) arranged on the substrate and adjacent to the working electrode, and a bio-recognition layer (16)arranged on the working electrode. USE - Biosensor for converting concentration or amount of biological analytes into measurable signals e.g. optical, electrical, electrochemical or other signals for detection. ADVANTAGE - The biosensor has simple, user-friendly, and rapid on-site detection tool of the pathogens, and detects river water contaminants and detection of pathogens. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a bio-sensing system which comprises a biosensor, and a detection device receiving signals from the biosensor; and (2) a method for preparing a biosensor, which involves: (a) providing a substrate; (b) forming a working electrode and a counter electrode on the substrate, where the counter electrode is adjacent to the working electrode, and the working electrode comprising a graphene layer; and (c) forming a bio-recognition layer on the working electrode. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of biosensor. Substrate (11) Working electrode (12) Counter electrode (13) Bio-recognition layer (16) Modification layer (122)