Boosting responses of fluorescent imaging probes toward sulfur dioxide through engineering side chain length

Kexin Pan; Liyuan Chen; Guangjun Tian; Juyue Zhou; Suying Xu; Leyu Wang

doi:10.1016/j.saa.2025.126252

Boosting responses of fluorescent imaging probes toward sulfur dioxide through engineering side chain length

Spectrochim Acta A Mol Biomol Spectrosc. 2025 Nov 5:340:126252. doi: 10.1016/j.saa.2025.126252. Epub 2025 Apr 23.

Authors

Kexin Pan¹, Liyuan Chen¹, Guangjun Tian¹, Juyue Zhou¹, Suying Xu², Leyu Wang³

Affiliations

¹ State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
² State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: syxu@mail.buct.edu.cn.
³ State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: lywang@mail.buct.edu.cn.

PMID: 40318266
DOI: 10.1016/j.saa.2025.126252

Abstract

Development of fluorescent probes with high sensitivity and specificity is always desirable, yet, challenging. Conventionally, improving the responses of probes relied on optimizing the reactivities of recognition sites, either by increasing the binding affinity or reaction rates. Herein, we found the sensitivity and response kinetics could be improved by changing the aggregation behaviors of probes. As a proof-of-concept, benzothiazole derivatives with different side chain lengths were prepared and the enhanced responses toward sulfur dioxide (SO₂) were observed for the probe with longer side chain. We demonstrated that the long side chain facilitates formation of tightly aggregates, which possessed higher positive charges and susceptible recognition sites as compared with probes possessing short side chains, resulting in better sensitivity and faster responses. In addition, we also demonstrated the generality of such design protocols with probes displaying aggregation induced emission (AIE) properties. Thus, the proposed side chain engineering strategy provides new paradigm for probe design.

Keywords: Enhanced responses; Fluorescent sensor; Side chain engineering; Sulfur dioxide detection.