▎ 摘　　要

NOVELTY - Synthesizing graphene quantum dot comprises (i) dissolving dextran in deionized water, stirring and dispersing for complete dissolving to obtain aqueous dextran solution; (ii) adding the aqueous dextran solution into a reaction kettle and hydrothermally reacting under pressure to obtain brownish-yellow solution; and (iii) centrifuging the brownish-yellow solution and separating the upper brownish-yellow transparent liquid as aqueous graphene quantum dot solution. USE - The graphene quantum dot is useful in biological field. ADVANTAGE - The method utilizes natural sustainable dextran as raw material, which is widely distributed in fungi and plants; and is simple, environmentally friendly and suitable for industrial production. The quantum dot has good water-solubility, fluorescence stability and biocompatibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for graphene quantum dot prepared by the above method, where the quantum dot has particle diameter of 1-3 nm and UV absorption characteristic peak of 225-283 nm.