Quinoline-based fluorescent probes with large Stokes shift for sequential Cu2+ and S2- ions detection in bioimaging

Yanling Long; Xiangjie Luo; Ruimin Xia; Ling Li; Zheng Li; Wenwei Sun; Hong-Ke Liu; Yong Qian

doi:10.1016/j.talanta.2025.128501

Quinoline-based fluorescent probes with large Stokes shift for sequential Cu²⁺ and S^2- ions detection in bioimaging

Talanta. 2025 Jun 23:296:128501. doi: 10.1016/j.talanta.2025.128501. Online ahead of print.

Authors

Yanling Long¹, Xiangjie Luo², Ruimin Xia¹, Ling Li¹, Zheng Li¹, Wenwei Sun¹, Hong-Ke Liu³, Yong Qian⁴

Affiliations

¹ Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China.
² Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China. Electronic address: xiangjieluo@qq.com.
³ Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China. Electronic address: liuhongke@njnu.edu.cn.
⁴ Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210046, China. Electronic address: yongqian@njnu.edu.cn.

PMID: 40570438
DOI: 10.1016/j.talanta.2025.128501

Abstract

Fluorescent probes offer a promising approach to detecting and imaging biologically essential copper (Cu²⁺) and sulfide (S^2-) ions, which play critical roles in various physiological processes. However, many existing Cu²⁺ and S^2- probes have limitations like narrow Stokes shifts. To address this, we rationally designed and synthesized three quinoline-based fluorescent probes (CuQP-1, CuQP-2, and CuQP-3), each incorporating a unique Cu²⁺ ion recognition group. Notably, CuQP-1 exhibited a substantial Stokes shift of 178 nm. Furthermore, CuQP-1 displayed selective fluorescence quenching upon interaction with Cu²⁺ ions, which was uniquely restored upon the subsequent addition of S^2- ions. Subsequent investigations revealed that CuQP-1 can effectively image Cu²⁺ and S^2- ions in HT22 cells and zebrafish, underscoring its potential as a versatile tool for studying these analytes in biological systems. In addition, the [CuQP-1 + Cu²⁺] complex is suitable for S^2- detection in real samples.

Keywords: Bioimaging; Copper ions; Fluorescent probe; Quinoline; Sulfide ions.