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.