A novel AIE-active camphor-based fluorescent probe for simultaneous detection of Al³⁺ and Zn²⁺ at dual channels in living cells and zebrafish

Abstract

A novel dual-functional probe <i>N</i>'-(2-hydroxy-5-((4,7,7-trimethyl-3-oxobicyclo[2.2.1] heptan-2-ylidene)methyl) benzylidene)picolinohydrazide (PSH) was constructed from natural camphor. This probe showed strong yellow-green fluorescence at 535 nm due to its aggregation-induced emission (AIE) feature. Interestingly, the probe PSH displayed a significant turn-on fluorescence response towards Al³⁺ (green fluorescence at 500 nm) and Zn²⁺ (orange fluorescence at 555 nm) at two different emissive channels. The detection limits of PSH towards Al³⁺ and Zn²⁺ were found to be 12.1 nM and 14.2 nM, respectively. PSH exhibited excellent selectivity and anti-interference performance and could distinguish between Al³⁺/Zn²⁺ and identify whether Zn²⁺ exists in the PSH-Al³⁺ complex by adding ATP. The binding mechanisms between PSH and Al³⁺/Zn²⁺ ions were supported by ¹H NMR, HRMS analysis, and density functional theory (DFT) calculations. Based on its outstanding sensing properties, the probe PSH was used to establish molecular logic function gates. Moreover, the probe PSH could be applied to detect Al³⁺ and Zn²⁺ in real environmental water, and fluorescence detection was well demonstrated by test strips. Furthermore, the probe PSH was employed for imaging Al³⁺ and Zn²⁺ in HeLa cells and zebrafish.