Faculty of Materials Science and Chemical Engineering , Ningbo University , 818 Fenghua Road , Ningbo 315211 , China.
Key Laboratory of Bio-Based Polymeric Materials Technology and Application of Zhejiang Province , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China.
ACS Sens. 2018 Nov 26;3(11):2394-2401. doi: 10.1021/acssensors.8b00835. Epub 2018 Oct 22.
Detection of a toxic formaldehyde (HCHO) pollutant in aqueous solutions is of significant importance, because HCHO is widely found in aquatic food because of illicit addition or improper storage. Many small-molecule-based fluorescent probes, which rely on HCHO-specific formaldehyde-amine condensation or the aza-Cope rearrangement reaction, have been developed in terms of facile operation and high selectivity. However, some primary challenging issues are the restricted sensitivity and long equilibrium response time caused by the slow chemical reaction between these small-molecule-based sensors and low-concentration HCHO pollutant in testing samples. Herein, a robust hydrophilic hydrazino-naphthalimide-functionalized chitosan (HN-Chitosan)-based polymeric probe is reported, which takes advantage of specific chemical reaction between HCHO and grafted hydrazino-naphthalimide groups to trigger a "turn-on" fluorescence response. Superior to its small-molecule analogs, HN-Chitosan is based on random coil polymer chains of biopolymeric chitosan, which is thus capable of employing the cooperative binding effect of multiple hydrazino-naphthalimide recognition sites and adjacent hydroxyl groups to "enrich" the low-concentration HCHO pollutant around the polymer chains via weak supramolecular interactions. Therefore, the HCHO-specific chemical reaction with grafted hydrazino-naphthalimide groups is significantly accelerated, resulting in the unprecedented ultrafast equilibrium fluorescence response (less than 1 min) and high sensitivity. Encouraged by its satisfying sensitivity, selectivity, fast response, and wide linear detection range, we successfully expand its application to real-world food and water analysis. In view of the modular design principle of our polymeric probe, the proposed strategy could be generally applicable to construct powerful polymeric probes for ultrafast detection of other important pollutants.
检测水溶液中的有毒甲醛（HCHO）污染物非常重要，因为由于非法添加或不当储存，HCHO 广泛存在于水生食品中。已经开发了许多基于小分子的荧光探针，这些探针依赖于 HCHO 特异性的甲醛-胺缩合或氮杂-Cope 重排反应，具有操作简单和高选择性的特点。然而，一些主要的挑战性问题是由于这些基于小分子的传感器与测试样品中低浓度 HCHO 污染物之间的化学反应缓慢，导致灵敏度受限和平衡响应时间长。在此，报道了一种坚固的亲水性肼基-萘酰亚胺功能化壳聚糖（HN-Chitosan）基聚合物探针，该探针利用 HCHO 与接枝肼基-萘酰亚胺基团之间的特定化学反应触发“开启”荧光响应。与小分子类似物相比，HN-Chitosan 基于生物聚合物壳聚糖的无规卷曲聚合物链，因此能够通过多个肼基-萘酰亚胺识别位点和相邻羟基的协同结合效应，通过弱超分子相互作用“富集”聚合物链周围的低浓度 HCHO 污染物。因此，接枝肼基-萘酰亚胺基团的 HCHO 特异性化学反应明显加速，导致前所未有的超快平衡荧光响应（不到 1 分钟）和高灵敏度。鉴于其令人满意的灵敏度、选择性、快速响应和宽线性检测范围，我们成功地将其应用扩展到实际食品和水分析中。鉴于我们的聚合物探针的模块化设计原理，所提出的策略可以普遍适用于构建用于超快检测其他重要污染物的强大聚合物探针。
