Determination of sulfhydryl amino acid content is of great importance for disease research. Therefore, it is necessary to develop a fluorescent probe that can detect sulfhydryl amino acids. In this paper, sixty-one 1,8-naphthoyl derivatives were successfully synthesized. These performances of compounds were measured by UV-Vis spectra and fluorescence spectra (FL). Unlike the non-fluorescent nitro-substituted compounds N-methyl-4-nitro-1,8-napthalimide (4a)~N-(m-fluorophenyl)-4-nitro-1,8-napthalimide (4s), the amino-substituted compounds N-methyl-4-amino-1,8-napthalimide (5a)~N-(m-fluorophenyl)-4-amino-1,8-napthalimide (5s) have strong yellow fluorescence, and the maleic anhydride-sub- stituted compounds N-methyl-4-(1H-pyrrole-2,5-diketone-1-yl)-1,8-napthalimide (6a)~N-(m-fluorophenyl)-4-(1H-pyrrole- 2,5-diketone-1-yl)-1,8-napthalimide (6s) have weak blue fluorescence. Of the 61 probes, 7 probes have fluorescent OFF-ON effect on cysteine (Cys) solutions. It was found that these probes have the potential to detect cysteine. The specificity of the probe for cysteine detection was explored by adding 21 amino acids as distracters. The fluorescence intensity at different pH values were studied. The response time between the detection probe and cysteine, and the variation of the fluorescence intensity of the probe solution with amino acid concentration were also studied. The linear correlation coefficients reached above 0.95. The response time of the probe was tested by fluorescence time spectral scanning. Through the above experiments, it was found that the probe showed a better sensitivity and selectivity for cysteine. The ability of seven fluorescent probes to be used for intracellular cysteine detection was explored by Hela cell fluorescence imaging and screened out probes with potential for biological detection.

Key words: synthesis, fluorescence molecular probe, cysteine, 1,8-napthalimide derivatives, cell fluorescence imaging