Design of Fe3O4@SiO2@Carbon Quantum Dot Based Nanostructure for Fluorescence Sensing,Magnetic Separation, and Live Cell Imaging of Fluoride Ion.

A robustreusable fluoride sensor comprised of a receptor in charge of thechemical recognition and a fluorophore responsible for signal recognitionhas been designed. Highly fluorescent carbon quantum dot (CD) andmagnetically separable nickel ethylenediaminetetraaceticacid (EDTA) complex bound-silica coated magnetite nanoparticle (Fe3O4@SiO2–EDTA–Ni) havebeen used as fluorophore and fluoride ion receptor, respectively.The assay is based on the exchange reaction between the CD and F–, which persuades the binding of fluoride to magneticreceptor. This method is highly sensitive, fast, and selective forfluoride ion in aqueous solution. The linear response range of fluoride(R2= 0.992) was found to be 1–20μM with a minimum detection limit of 0.06 μM. Excellentmagnetic property and superparamagnetic nature of the receptor areadvantageous for the removal and well quantification of fluoride ion.The practical utility of the method is well tested with tap water.Because of high sensitivity, reusability, effectivity, and biocompatibility,it exhibits great promise as a fluorescent probe for intracellulardetection of fluoride. [ABSTRACT FROM AUTHOR]