A NIR dual-channel fluorescent probe for detecting viscosity and ONOO^- in vitro and vivo

Aberrant viscosity and excessive levels of peroxynitrite (ONOO^-) in organism system often result in biological dysfunction and even diseases. Hence, it is crucial to construct near-infrared (NIR) dual-response fluorescent probes for simultaneous detection of viscosity and ONOO^-. Herein, we fabricated a NIR fluorescent probe (TCPB) with a large emission shift, enabling independent dual-response determination of viscosity and ONOO^- in living cells. TCPB contained a D-π-A unit with twisting intramolecular charge transfer (TICT) sensitive viscosity and a phenylborates unit responsive to ONOO^-, and a pyridine cation unit with mitochondrial localization. The results showed TCPB can respond sensitively to viscosity and ONOO^- at 709 and 460 nm, which ensured to simultaneously monitoring the viscosity and ONOO^- in two channels without signal crosstalk. Meanwhile, the image results showed TCPB can visualize endogenous and exogenous cellular viscosity and ONOO^-, differentiate between cancer cells and normal cells. and detect viscosity in inflamed mice. Hence, TCPB offered a potential tool for understanding occurrence and development research of related illnesses via simultaneous detection of viscosity and ONOO^-.