Sustainable Synthesis of Fe3+-Responsive Fluorescent Probes from Crab Shell Waste-Derived Chitosan

作者：Yifan Ren, Jingnan Hu, Huan Chen, Yutong Ye, Ruiqi Zhang, Rui-Yu Mi · 发表于：Nanomaterials · 年份：2026 · DOI：10.3390/nano16150933 · 研究领域：Medicine

It is crucial to develop advanced fluorescence sensing platforms for precise detection of metal pollutants in environmental monitoring. However, traditional fluorescent probes are often limited by aggregation-caused quenching (ACQ). In contrast, clusterization-triggered emission (CTE) probes, based on non-conjugated systems, exhibit excellent photostability by relying on spatial clusterization to restrict molecular motion. Crab shells, an abundant aquatic waste, are rich in chitin (20–30%). Following deacetylation, chitin is converted into chitosan, a biocompatible and biodegradable biopolymer with excellent potential for chemical modification. In this study, a novel chitosan-based CTE fluorescent probe (CS-FA) was synthesized via a facile cross-linking condensation reaction between chitosan and formaldehyde. This process successfully restricts intramolecular motion and promotes the tight clustering of electron-rich heteroatoms, thereby activating the CTE mechanism. The resultant CS-FA probe exhibits strong and stable blue fluorescence and demonstrates high selectivity and sensitivity toward Fe3+ in aqueous media. In the concentration range of 10–100 µM, the fluorescence intensity decreases linearly with the Fe3+ concentration, yielding a competitive limit of detection (LOD) of 0.52 µM. Mechanistically, the specific coordination between Fe3+ and the cross-linked polymer provides a dominant non-radiative decay pathway, leading to significant fluorescence quenching. Ultimately,...