A selective BODIPY-based fluorescent sensor for the detection of Cu²⁺ ions in biological and environmental samples

In this study, we present the design, synthesis, and characterization of a 'turn-on' fluorescent probe, BOD-HDZ, for the selective detection of Cu²⁺ ions in semi-aqueous solutions, environmental samples (water and soil), and MCF-7 cancer cells. BOD-HDZ was synthesized by functionalizing meso-formyl-BODIPY (BOD-ALD) with a 2-hydrazinopyridine, resulting in fluorescence quenching via a photoinduced electron transfer (PET) mechanism. The 1:1 coordination between Cu2⁺ and the probe was confirmed through Job's plot analysis and 1H NMR spectroscopy, leading to a 210-fold fluorescence enhancement at 515 nm. BOD-HDZ demonstrated exceptional sensing properties, including a rapid response time (<1 min), a broad operational pH range (2-12), and high sensitivity with a detection limit of 141 nM.