▎ 摘　　要

NOVELTY - Preparation of graphene quantum dot with controllable fluorescence color involves dispersing graphene quantum dot powder in N,N-dimethylformamide, performing ultrasonic reaction and rotary evaporation drying, subjecting dried dot to column chromatography, adding aqueous solution of obtained graphene quantum dot, mixed aqueous solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxyl succinimide, and alkylamine, adding aqueous solution of obtained alkylamine-modified graphene quantum dot and sodium borohydride, performing dialysis, and removing sodium ion. USE - Preparation of graphene quantum dot used for two-photon biological imaging. ADVANTAGE - The method provides graphene quantum dot exhibiting controllable fluorescence color and having favorable up-conversion fluorescence property, with reduced damage of ultraviolet excitation on organisms during fluorescent substance imaging process. DETAILED DESCRIPTION - Preparation of graphene quantum dot with controllable fluorescence color by chemical modification involves preparing green fluorescent graphene quantum dot by dispersing 50-200 mg graphene quantum dot powder in 10 mL N,N-dimethylformamide, performing ultrasonic reaction, transferring obtained product to stillage, reacting at 150-300 degrees C for 5-20 hours, performing rotary evaporation drying of obtained reaction supernatant to obtain dry graphene quantum dot, and subjecting dry graphene quantum dot to two-step gradient column chromatography to obtain green fluorescent graphene quantum dot, preparing alkylamine-modified green fluorescent graphene quantum dot by adding 10 liter aqueous solution containing 0.5-1 g/l green fluorescent graphene quantum dot, and 100-500 mu l mixed aqueous solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxyl succinimide, stirring reaction system at room temperature, adding 30-50 mu l alkylamine, stirring at room temperature for 4-6 hours, and again stirring at 80-100 degrees C for 2-4 hours to obtain alkylamine-modified green fluorescent graphene quantum dot, chemically reducing alkylamine-modified green fluorescent graphene quantum dot by adding 10 liter aqueous solution containing 0.5-1 g/L alkylamine-modified green fluorescent graphene quantum dot and 30-50 mg sodium borohydride, stirring reaction system for 4-6 hours, performing dialysis of obtained reaction product having molecular weight of 1000 using dialysis bag, and removing sodium ion to obtain graphene quantum dot with controllable fluorescence color.