A Rational Designed Bioorthogonal Surface-Enhanced Raman Scattering Nanoprobe for Quantitatively Visualizing Endogenous Hydrogen Sulfide in Single Living Cells.

Understanding the biology of gasotransmitters in living cells is of significance but remains challenging due to largely a lack of robust molecular probes. Here, we present the facile design and synthesis of a bioorthogonal Raman probe, 4-azidobenzenethiol (4-ABT), for endogenous hydrogen sulfide (H2S) imaging in single live cells by surface-enhanced Raman scattering (SERS). 4-ABT bears a thiol group and an azido group in the benzene ring, thus affording a bifunction to firmly bind to the gold nanoparticle surface and specifically respond to H2S. Moreover, the 4-ABT-based SERS nanoprobe shows a dose-dependent spectral change in the cellular Raman-silent region upon reacting with H2S, allowing ratiometric quantitative detection and visualization of intracellular H2S status without bio-interference. The ease of fabrication and superior performance of the novel SERS nanoprobe demonstrate its promising application in studies of H2S-related signaling networks.