Quinoline derivative-functionalized carbon dots as a fluorescent nanosensor for sensing and intracellular imaging of...

Surface functionalization of nanomaterials with highly specific recognition elements, such as biomolecules and organic molecules, has made possible many novel nanosensors for bio/chemical analysis and target bioimaging. In this report, a fluorescent nanosensor which exhibits highly specific recognition capability towards Zn²⁺ over competing metal ions has been developed through covalently functionalizing carbon dots (C-dots) with the quinoline derivatives which show response to Zn²⁺. The nanosensor exhibits excellent water solubility, biocompatibility, and cell-membrane permeability, and demonstrates high selectivity towards Zn²⁺ with a detection limit as low as 6.4 nM. Additionally, the rapid response of the nanosensor towards Zn²⁺ can be achieved within 1 min. The large amount of recognition units on the outer surface of an individual nanoparticle enables the signal amplification, hence making the immediate and highly sensitive detection of Zn²⁺ possible. Therefore, a reliable and highly specific nanosensor has been demonstrated for both rapid quantitative detection of Zn²⁺ in aqueous solution and real-time imaging of intracellular Zn²⁺, suggesting its potential and significance in bioanalysis and biomedical detection in the future.