Quinoline-based fluorescent probe for the detection and monitoring of hypochlorous acid in a rheumatoid arthritis model

• Published in: RSC advances Vol. 11; no. 5; pp. 31656 - 31662
• Main Authors: Yang, Xinyi, Wang, Yue, Shang, Zhuye, Zhang, Zexi, Chi, Haijun, Zhang, Zhiqiang, Zhang, Run, Meng, Qingtao
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 24.09.2021; The Royal Society of Chemistry
• Subjects: Arthritis; Benzoquinone; Chemistry; Chromatography; Doppler effect; Fluorescent indicators; High performance liquid chromatography; Hydroxybenzaldehydes; Inflammatory response; Monitoring; Oxidation; Quinoline; Reaction mechanisms; Red shift; Response time; Rheumatoid arthritis; Selectivity; Telemedicine; Titration; Toxicity; Visualization; Water sampling
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d1ra06224g

The development of effective bioanalytical methods for the visualization of hypochlorous acid (HOCl) in situ in rheumatoid arthritis (RA) directly contributes to better understanding the roles of HOCl in this disease. In this work, a new quinoline-based fluorescence probe ( HQ ) has been developed for the detection and visualization of a HOCl-mediated inflammatory response in a RA model. HQ possesses a donor-π-acceptor (D-π-A) structure that was designed by conjugating p -hydroxybenzaldehyde (electron donor) and 1-ethyl-4-methylquinolinium iodide (electron acceptor) through a C&z.dbd;C double bond. In the presence of HOCl, oxidation of phenol to benzoquinone led to the red-shift (93 nm) of the adsorption and intense quenching of the fluorescence emission. The proposed response reaction mechanism was verified by high performance liquid chromatography (HPLC) and high-resolution mass spectroscopy (HRMS) titration analysis. The remarkable color changes of the HQ solution from pale yellow to pink enabled the application of HQ -stained chromatography plates for the "naked-eye" detection of HOCl in real-world water samples. HQ featured high selectivity and sensitivity (6.5 nM), fast response time (<25 s) to HOCl, reliability at different pH (3.0 to 11.5) and low cytotoxicity. HQ 's application in biological systems was then demonstrated by the monitoring of HOCl-mediated treatment response to RA. This work thus provided a new tool for the detection and imaging of HOCl in inflammatory disorders. A quinoline-based fluorescent probe ( HQ ) has been designed and synthesized for the monitoring of HOCl-mediated treatment response of a rheumatoid arthritis (RA) model and "naked-eye" detection of HOCl in real water samples.