Employment of the fluorescent probe hydroxy-naphthyl-methylbenzoxazole-based dye and its combination with fluorescent silica nanoparticles as potential heavy metal-targeting systems: results and troubleshooting in Cd-polluted environments

: To address the critical need for monitoring heavy metal (HM) contamination in living systems, this study evaluates a novel HNBO-based fluorescent probe for the detection of cadmium (Cd) in human cell lines and mussel hemocytes. Both the free probe (HNBO-DEN) and its conjugate with core-shell silica nanoparticles (HNBO-DEN-NPs) demonstrated robust Cd-sensing capabilities without compromising cellular viability. The key findings include targeted detection (the fluorescent probe successfully identified cadmium in bioindicators, providing a real-time alternative to traditional, destructive analytical techniques) and dual system efficiency: both free and silica NP-conjugated probes (HNBO-DEN-NPs) proved effective although to a different extent and with their own peculiarities: while HNBO-DEN is more effective at detecting Cd concentrations in the cytoplasm, the NP conjugate proves more suitable for detecting the metal in its target and storage organelles. The combined use of these probes may account for precise, live-cell tracking of both pollutant (Cd) and detector (NP), maximizing diagnostic, environmental, and cytological information.