Hydrogen Sulfide-Activated Background-Free Self-Referenced Surface-Enhanced Raman Scattering Nanoprobe for Real-Time...

Accurate quantification and real-time monitoring of hydrogen sulfide (H2S) dynamics are critical for the early diagnosis and therapeutic intervention of liver injury, but remain challenging. Herein, we first report an activatable, background-free, ratiometric surface-enhanced Raman scattering (SERS) nanoprobe (Au@MBN@Au@PB, AMAP) for quantitative and real-time monitoring of H2S during liver injury progression. The AMAP nanoprobe features a 4-mercaptobenzonitrile (MBN)-encoded gold core as an internal standard, combined with an H2S-responsive Prussian blue (PB) shell. Crucially, both Raman reporters exhibit distinct vibrational fingerprints exclusively within the biologically silent window (1800-2800 cm-1), eliminating endogenous spectral interference. Upon H2S activation, the PB shell undergoes in situ decomposition, leading to a concentration-dependent attenuation of the PB signal (IPB), while the MBN signal (IMBN) remains unchanged. This enables accurate and sensitive ratiometric quantification of H2S (IPB/IMBN) with a detection limit of 3.05 μM. Besides, the nanoprobe can detect both exogenous and endogenous H2S fluctuations in living cells. More importantly, using this nanoprobe, we monitor the progression of metformin (MET)-induced liver injury via real-time SERS detection of H2S dynamics at both cellular and tissue levels. This work provides a versatile platform for precise and dynamic monitoring of H2S-associated pathological processes, opening new avenues for early diagnosis and mechanistic studies of liver diseases.