A simple dual-response fluorescent probe for imaging of viscosity and ONOO through different fluorescence signals in living cells and zebrafish.

Cellular viscosity is a prominent micro-environmental parameter and peroxynitrite is an essential reactive oxygen special, both of which are involved in various pathological and physiological processes. When the intracellular viscosity is abnormal or the ONOO concentration is irregular, the normal function of cells will be disturbed. Herein, we rationally designed and synthesized a novel multichannel fluorescent probe (probe 1) for multichannel imaging of viscosity and peroxynitrite. Probe 1 displayed about 108-fold enhancement as the viscosity increased from 1.005 cP to 1090 cP. Moreover, the fluorescence intensity at 540 nm was quickly increased after adding ONOO. It should be noted that probe 1 has high sensitivity, selectivity and low cytotoxicity, which can be successfully employed for the visualization of exogenous and endogenous ONOO and imaging viscosity changes in HeLa cells by different fluorescent signals. Furthermore, probe 1 could monitor the change of ONOO induced by LPS (lipopolysaccharide) and IFN-γ (interferon-γ) in zebrafish. This result reveals that probe 1 may inspire more diagnostic and therapeutic programs for viscosity-peroxynitrite related diseases shortly.