Rational construction of a fluorescent sensor for simultaneous detection and imaging of hypochlorous acid and peroxynitrite in living cells, tissues and inflammatory rat models.

Modern medical research indicates that hypochlorous acid (HClO) and peroxynitrite (ONOO) are important biomarkers of oxidative stress. However, the up- or down-regulation of HClO or ONOO has been closely associated with the occurrence and development of various diseases. In order to investigate the intrinsic entanglement relationship between HClO and ONOO and their relationship with the occurrence and development of inflammation, it is very valuable to develop fluorescent sensors that are capable of displaying different signals towards HClO, ONOO and HClO/ONOO. In this work, we rationally design and construct a novel robust small organic molecule fluorescent sensor (RhNp-ClO-ONOO) towards ONOO, HClO and HClO/ONOO with green, red, and green-red three different fluorescent signal outputs, respectively. RhNp-ClO-ONOO has fast responsive time for HClO (∼60 s) and ONOO (∼20 s). Also it has markedly low detection limits for HClO (∼25.3 nM) and ONOO (12.4 nM) respectively. In addition, RhNp-ClO-ONOO could be further shown to detect endogenous HClO/ONOO in living cells, inflammatory tissues and rat model successfully. Therefore, this novel fluorescent sensor with double responsive moiety can offer a powerful tool for studying the role of HClO and ONOO and the occurrence and development of inflammatory diseases.