One-step hydrothermal synthesis of fluorescent silicon nanoparticles for sensing sulfide ions and cell imaging.

We have presented a hydrothermal approach for synthesizing fluorescent silicon nanoparticles (F-SiNPs) with yellow-green emission. The obtained F-SiNPs exhibited excellent stability and good biocompatibility. By virtue of the specific reaction between S2- and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), colorimetric assay of S2- was realized with a good linear range of 0-100 μM. The colorimetric detection system could be further combined with F-SiNPs to construct a probe for fluorescence turn-off sensing S2- in aqueous solution due to inner filter effect. In the fluorescent detection system, a good linearity with S2- concentration in the range of 0-50 μM was accomplished. And as low as 0.1 μM S2- was successfully detected. Moreover, the F-SiNPs displayed low cytotoxicity and good biocompatibility, and was further utilized for cell imaging. These results demonstrated the promising applications of F-SiNPs in S2- analysis and bioimaging.