Triphenylamine-Based Polythioacetal for Selective Sensing of Mercury(II) with High Specificity and Sensitivity
Yu Gu, Ruixin Jia, Yue Yu, Siyong Li, Jianjian Zhu, Xinxin Feng, Yanbing Lu
Abstract
Utilizing the mercury (Hg 2+ )-triggered deprotection of thioacetals to aldehyde groups, we constructed a water-soluble triphenylamine (TPA)-based polythioacetal PTA-TPA with thioacetal groups in the backbones for efficient sensing of Hg 2+ in aqueous solutions. PTA-TPA is conveniently prepared by polycondensation of 3, 6-dioxa-1,8-octanedithiol (DODT) with 4-( N, N -diphenylamino) benzaldehyde (TPA-CHO) using thiol-terminated mPEG2k-SH as a capping agent. The interaction of Hg 2+ with PTA-TPA activates the aggregation-induced emission (AIE) process of TPA-CHO molecules, which makes the emission enhanced, and the emission color changes to sky blue, while other metal ions do not interfere with the sensing process. PTA-TPA can be used as a highly selective and ultrafast detection system for Hg 2+ with a low detection limit (LOD) of 9.88 nM and a fast response of less than 1 min. In addition, the prepared test strips report the presence of Hg 2+ with an LOD as low as 1 × 10 –5 M. Intracellular imaging applications have demonstrated that PTA-TPA acts as a biocompatible fluorescent probe for efficient Hg 2+ sensing in HeLa cells. Overall, the PTA-TPA fluorescence probes have the characteristics of easy synthesis, cost-effective, ultrafast detection speed, high selectivity, and high sensitivity, which can be used in practical applications.