Insight into Cys and its derivatives metabolism in living system with 3D-printed portable smartphone platform via...

Cysteine (Cys) is a crucial biological thiol that facilitates broad range of biological circumstances and health conditions. Especially the aberrant Cys level in human serum is an independent risk factor for cardiovascular diseases. What more, Cys metabolism (Cys to SO₂) is typically connected with illnesses such as lung cancer, and are recognized as biomarker. Herein, an innovative multifunctional fluorescent probe was rudimentarily designed and utilized, not only for realizing real-time visualization of the metabolism of Cys to SO₂ in tumors through two self-sufficient channels without spectral cross-interference, but also for sensitive, real-time, on-site, and quantitative visual recognition of Cys in human serum through 3D-printed smartphone sensing platform. In addition, the probe's unique response to Cys/HSO₃^- in distinct spectral behaviors, which have been characterized theoretically using UV-Vis, fluorescence, DFT calculations, and ¹H NMR. More importantly, the methodology reported herein enables an available pathway for real-time/on-site and visual determination of Cys in human serum and is expected to extend the use of potential cardiovascular disease biomarker studies for initial monitoring and clinical diagnosis.