A novel NIR fluorescent probe for monitoring cysteine in mitochondria of living cells

Abstract

It has been demonstrated that the results caused by abnormal levels of Cysteine (Cys) are not negligible in biological processes. Furthermore, mitochondria are one of the most important organelles, which not only produce cellular energy, but also participate in signal transmission, growth, death, and other biological processes. Therefore, developing an efficient fluorescent probe targeting mitochondria to detect Cys in cells is useful for clinic pathological diagnosis. In this report, a near-infrared (NIR) fluorescent probe LAA based on link-anthocyanin as fluorophore and acrylate as identification groups has been prepared. Link-anthocyanin, as an NIR-emitting fluorophore, showed favorable water solubility and strong fluorescence intensity. Acrylate, as a recognition site, exhibited intense sensitivity and selectivity to Cys. In addition, LAA had a high tendency to localize to mitochondria due to the lipophilic positive ion in the link-anthocyanin. Under the excitation of 560 nm, the probe LAA could detect Cys with high selectivity and low detection limit (37 nM) at the emission of 670 nm, which belonged to the NIR range and was beneficial for biological application. Furthermore, LAA exhibited great biocompatibility and low cytotoxicity, which could monitor Cys in mitochondria of living cells in real-time.