▎ 摘　　要

NOVELTY - A fluorescent labeling kit is a graphene-based tumor cell nuclear targeting fluorescent nanoprobe (GTTN) solution with a particle size of 3-5 nm and a concentration of 10-30 mg/L. USE - Kit is used for fluorescent labeling of tumor cell nucleus of biological sample such as cells, animal tissues, and live animals (all claimed). ADVANTAGE - The fluorescent labeling kit enables long-term stable fluorescent labeling of tumor cell nucleus with clear and stable imaging, by simple, quick, easy-to-operate, and practicable method. The fluorescently-labeled nucleus features strong photoquenching resistance. It is unnecessary to crosslink the GTTN with guiding molecules for nuclear localization, such as antibodies and nuclear localization signals, but the selective localization of nucleus is directly realized using the unique chemical advantages of GTTN, saving the intermediate step. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for fluorescent labeling of a cell nucleus, which involves immobilizing a biological sample with 4% paraformaldehyde, co-incubating GTTN with the biological sample at room temperature for 5 minutes, with a surface of the biological sample covered by the GTTN, and washing off excess GTTN from the surface of the biological sample by a phosphate-buffered saline buffer system, and observing the cell nucleus of the biological sample under 405 nm excitation light irradiation.