Imidazole-Centred Oxadiazole Sensor for Detecting Al3+ and Fe3+ Cations in Living Cells: A Zebrafish Bioimaging Approach

Abstract

This study introduces a novel organic fluorescent chemosensor, designated as imidazole 4-(1-(4-(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)-N,N-diphenylaniline (TIMTB). Engineered specifically for detecting aluminium (Al³⁺) and iron (Fe³⁺) ions, TIMTB demonstrates exceptional selectivity, rapid response times, and efficacy in complex matrices such as biological fluids and environmental samples. Comprehensive evaluations through UV absorption, fluorescence spectroscopy, and pH-dependent studies confirm TIMTB's high sensitivity and selectivity towards Al³⁺ and Fe³⁺. Further, the study was supported by Density Functional Theory (DFT) studies. TIMTB, synthesized with an imidazole-oxadiazole core, exhibited significantly low cytotoxicity (14 ± 0.15 μM). In aqueous ethanol medium, the probe achieved notably low detection limits of 2 nM for Fe³⁺ and 2.19 μM for Al³⁺. Minimal cytotoxicity was observed in both in-vitro (MDA-MB-231 cells) and in-vivo (zebrafish, Danio rerio) studies, paving the way for its application in tracing intracellular Al³⁺ ions in zebrafish embryos. TIMTB's robust performance underscores its potential as an invaluable tool for environmental monitoring and biomedical applications.