▎ 摘　　要

NOVELTY - Graphene quantum dot (GQDs) comprises polyethyleneimine (PEI) and 1,3,6-trinitrotoluene pyrene under hydrothermal reaction conditions to form graphene quantum dot modified by PEI (GQDs-PEI), and by amidation reacting to 4-carboxylic-butyl triphenyl phosphonium bromide (TPP), and grafting to GQDs construction of GQDs-TPP surface of the PEI. USE - The graphene quantum dot is useful for specific imaging of nuclei and mitochondria (claimed). ADVANTAGE - The GQDs: has biocompatibility and optical properties; specifically target the nucleus and mitochondria. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing GQDs comprising (i) mixing PEI with 1,3,6-trinitrotoluene pyrene for 3-5 hours after mixing evenly, transferring the mixed solution to a reaction kettle, reacting for 10-20 hours at 180-220 degrees C, naturally cooling the reaction kettle to room temperature, (ii) filtering the solution obtained in the step (i) on a micro porous membrane to removing larger sized carbon particles and insoluble matter, (iii) placing the filtrate in a dialysis bag with a molecular weight of 1000 for dialysis, and replacing water every 6 hours for 3 days, (iv) freeze drying the GQDs-PEI solution prepared in the step (iii) to obtain GQDs-PEI powder, (v) diluting the obtained GQDs-PEI powder in phosphate buffered saline to obtain different concentrations of GQDs-PEI, co-culturing with HeLa cells, and testing for cytotoxicity, and (vi) using graphene quantum dot for specific nuclear imaging for specific imaging of a cell nucleus.