▎ 摘　　要

NOVELTY - A nanocomposite comprises graphene quantum dots (GQDs) , where GQDs are coupled to surface of amino functionalized silicon dioxide nanosphere to use DNA at both ends of carboxyl group and amino group to make silicon dioxide/GQDs and gold nanoparticles (AuNPs) to link together with DNA for obtaining silicon dioxide/GQDs-DNA-AuNPs nanocomposite. USE - Nanocomposite for use in fluorescent biosensor that is utilized for sensitive detection of BLM (all claimed). ADVANTAGE - The nanocomposite is prepared with easy usability, stable optical property, high luminous intensity and good biological compatibility in an easy, simple and environment-friendly manner by easily modifying its surface. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a method for preparing the nanocomposite, which involves obtaining product A by dispersing SiO2 nanosphere in GQDs solution, stirring, treating SiO2 nanosphere surface with amino group, activating GQDs solution with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and n-hydroxysuccinimide (NHS) followed by slowly adding 80-100 mu l DNA to 1-2 ml AuNPs, aging the solution at 4-8 degrees C for 15-20 hours, adding 10-20 mM phosphate buffer for every 7-9 hours to the solution, adding 0.2-0.4 M sodium chloride solution to the solution, aging the solution, centrifuging the solution, washing obtained red precipitate using buffer, redispersing labeled AuNPs-DNA in phosphate-buffered saline, storing to obtain product B and centrifuging the product A and product B at room temperature for 2-3 hours (2) a fluorescent biosensor for sensitive detection of bleomycin (BLM).