Nanoliposomal Ratiometric Fluorescent Probe toward ONOO^- Flux

Peroxynitrite (ONOO^-), a powerful biological oxidant, is produced in the mitochondria and reacts with many biomolecular targets under various pathological conditions, leading to a range of disease states. In this work, we developed a nanoliposome-encapsulated ratiometrically fluorescent probe (NRF) based on a hemicyanine structure Cy-O obtained by facile synthesis. Upon reaction with ONOO^-, the oxidation and hydrolysis of a π-conjugation system within the nanoliposome triggers a ratiometrically fluorescent response and a large-scale emission shift (238 nm), which provides a specific and sensitive means for the ONOO^- detection. Moreover, we have performed DFT calculation at the 6-31+G(d,p) level using a suite of Gaussian 09 programs to obtain insights into the chemical structure optical properties of Cy-O. In addition, the practical applications of the nanoprobe to image exogenous and endogenous ONOO^- were achieved further in live cells and animals triumphantly.