Ionophore-based nanospheres enable selective and sensitive fluorescence detection of copper ions

A novel ionophore-based fluorescent nanosensor has been successfully fabricated for the sensitive and selective detection of Cu 2+ ions. The nanosensor was constructed through self-assembly of amphiphilic block copolymers, incorporating elesclomol as a Cu 2+ ionophore and long-chain dialkylcarbocyanines (DiD) as a fluorescent dye. This design exhibits an "ON/OFF" fluorescence response, where Cu 2 ⁺ ions are selectively sequestered within the nanosensors, resulting in fluorescence quenching of DiD. This strategy enables rapid and highly selective Cu 2 ⁺ sensing with remarkable fluorescence quenching efficiency (up to 93.5 %) and an exceptionally low detection limit of 28.6 nM. The linear detection range extends over two orders of magnitude (0.05–10 μM). Furthermore, the feasibility of this nanosensor for practical applications was confirmed through successful determination of Cu 2+ in real water and beer samples, with excellent recovery rates. This nanosensor offers advantages of simplicity, rapidity, and cost-effectiveness, holding significant potential for sensitive and selective Cu 2+ detection in various biological and environmental samples.