Next-Generation Fluorescent Chemosensor for Dual-Mode Detection of Aluminium Ions and DCP: A Bridge Between Sensing and Bio-imaging

Abstract

In the present work, we have rationally designed and synthesized a bis-naphthalimide-based “Turn-on” fluorescent chemosensor, BINNA, capable of dual-analyte recognition with high sensitivity and selectivity for aluminium ions (Al³+) and the nerve agent mimic diethyl chlorophosphate (DCP) in methanol medium. Distinct photophysical responses are observed: the addition of DCP induces a strong emission band at 370 nm, whereas the addition of Al³+ ions display an intense emission band at 450 nm, allowing for clear spectral discrimination. The probe demonstrates outstanding detection capabilities, with detection limits reaching as low as 8.5 nM for DCP and 18.2 nM for Al³+. High-resolution mass spectrometry (HRMS) analyses provides mechanistic insights into the interaction pathways of BINNA with each target analyte. Complementary theoretical investigations using computational modelling further corroborate the experimental findings. Beyond its role in solution-phase sensing, BINNA’s photonic properties are employed to construct a molecular logic gate system based on fluorescence signal outputs. The practical applicability of the sensor is validated through the successful detection of DCP and Al3+ in soil samples. Moreover, BINNA’s ability to visualize cellular uptake and fluorescence in live bacterial cells underscores its potential as a multifunctional probe for environmental analysis and advanced bio-imaging applications.