▎ 摘　　要

NOVELTY - Molecular beacon sensor comprises graphene quantum dots, which are successively arranged, first beacon stem region, an annular region, second stem region and beacon fluorophore. The annular region is measured with a nucleotide fragment, which specifically binds a target molecule. The nucleotide sequence of second region of the stem of the beacon stem region is the first sequence. USE - Molecular beacon sensor used for preparing kit used in detection of deoxyribonucleic acid, micro ribonucleic acid or messenger ribonucleic acid (claimed). DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a method for preparing molecular beacon sensor, which involves connecting end to end by the pyrene, first beacon stem region, an annular region, the first two beacons stem region and a fluorescent group, sequentially, where the fluorescent group consist of fluorescent probe, which is mixed with graphene quantum dot and the molecular beacon sensor is obtained; and (2) a method for detecting disease of target molecule, which involves mixing first target molecule and analyte as graphene-based molecular beacons sensor and then detecting by fluorescence.