Dual-channel fluorescent probe utilizing hydrazone for Zn2+ and Hg2+ detection: Exploring distinct signaling mechanisms and applications in bioimaging and latent fingerprint analysis.

[Display omitted] • Hydrazone based dual mode fluorescence sensor for Zn2+ ("turn-on") and Hg2+ ("turn off"). • Probe C1 selectively sense Zn2+and Hg2+ ions with their lowest detection limits 0.042 μM and 0.081 μM respectively. • The designed probe C1 was studied latent fingerprint analysis in various surfaces. • Live cell imaging studies was performed for probe C1 in presence and absence of Zn2+, Hg2+ ions. A facile Schiff base probe C1 has been developed and evaluated using 1H, 13C NMR, and mass spectroscopy. Fluorescence investigations were conducted to determine probe-sensing behavior. Probe C1 demonstrated sensitive, and selective recognition of Zn2+ and Hg2+ ions by using two distinct processes (i.e., chelation enhanced fluorescence effect and fluorescence quenching) over other cations in ACN-H 2 O (8:2, v/v). The Zn2+ and Hg2+ detection limits of 0.042 and 0.081 μM are achieved with the probe C1. C1 has a binding constant of 3.33 × 103 M−1 for Zn2+ and an emission quenching constant of 1.22 × 104 M−1 for Hg2+. A Jobs plot was used to determine the binding stoichiometry of C1 and Zn2+/Hg2+ ions ratio is 1:1. By using Zn2+/Hg2+ and EDTA additions alternately, the probe's reusability was investigated. Moreover, the probe was found to be highly cytocompatibility using an MTT assay in a mouse fibroblast cell line (NIH3T3). Further, the probe was found to visualize Zn2+ and Hg2+ ions inside the cells, indicating the potential application of the probe as an intracellular probe to detect Zn2+ and Hg2+ ions. The probe shows very good solid-state emission behavior, this motivates us to develop latent fingerprint detection and anticounterfeiting applications. [ABSTRACT FROM AUTHOR]