Engineered Reactive Interfaces Enable Mass Spectrometry Imaging of Multiple Thiols for Decoding PFOS-Induced Redox...

Spatial profiling of multiple thiols shows great significance in elucidating the redox status across tissue microregions and understanding the molecular mechanisms of oxidative stress injury. Traditional matrix-assisted laser desorption/ ionization mass spectrometry imaging (MALDI MSI) relies on chemical derivatization for thiol visualization, but multistep derivatization protocols and nonspecific matrix-adduct formation compromise both detection sensitivity and spatial mapping fidelity. Herein, we engineer a reactive interface-assisted chemical derivatization platform for sensitive assessment of multiple thiols in various tissues via forming the "matrix-tissue-interface" sandwich structure. Reactive interface that predeposited with N-(9-Acridinyl) maleimide (NAM) probes enables profile multiple thiols including cysteamine (MEA), cysteine (Cys), cysteinyl-glycine (Cys-Gly), glutathione (GSH), and ergothioneine (ET) across various tissues. The increased sensitivity is likely due to the accelerated reaction efficiency that arises from the locally high NAM concentrations in the tissue-NAM interface, coupled with the sandwich architecture that mitigates ion suppression of NAM probes and prevents matrix-NAM interaction. The results demonstrated distinct tissue-specific distribution patterns of various thiols as well as redox dysregulation of kidney induced by PFOS exposure. This innovative MSI methodology offers a robust route to enhance the derivatization performance for low-abundance molecule imaging, facilitating the investigation of oxidative stress-related disease mechanisms and the toxicological effects of pollutant.