Quantitative detection and cellular imaging of hydrogen sulfide using a SERS probe based on AuAg nanocages.

Hydrogen sulfide (H2S), a crucial gasotransmitter, plays an essential regulatory role in various physiological and pathological processes. There is an urgent need to develop sensitive and effective detection methods for intracellular H2S, as abnormal H2S levels are closely related to various diseases such as tumors. Herein, a surface-enhanced Raman scattering (SERS) probe was constructed for quantitative detection and imaging of H2S in living cells. The SERS probe was obtained by using gold silver alloy nanocages (AuAg NCs) with superior plasmonic activity as SERS substrate, followed by modification with Raman signal molecule (4-ethynylaniline), mucin1 aptamer and polyethylene glycol. Upon exposure to H2S, Ag in the SERS probe was rapidly and specifically converted to Ag2S, leading to a remarkable decrease in the SERS intensity of the probe at 2010 cm-1, a spectral region within the cell silent region. The developed SERS probe exhibited outstanding performances, including high sensitivity (with a detection limit as low as 0.36 nM for H2S), remarkable selectivity, excellent stability and minimal cytotoxicity. Notably, this SERS probe had been successfully applied for the detection and imaging of both endogenous and exogenous H2S levels in single living cells without bio-interference, highlighting its potential for precise and accurate intracellular H2S monitoring. This advancement provides a powerful tool for studying H2S-related physiological processes and disorders.