Highly luminescent N-doped carbon dots as a fluorescence detecting platform for Fe³⁺ in solutions and living cells

Iron (Fe³⁺) is one of the most essential elements in the human body; deficiency or overdose of Fe³⁺ may have adverse effects on human health and immunity. Hence, it is essential to establish a sensitive and selective method for ion detection. In this study, novel green fluorescent N-doped carbon dots (N-CDs) were prepared with caffeic acid as the carbon source via a simple hydrothermal method. The solution of the as-prepared N-CDs exhibits 21.5% quantum yield, good salt stability, excellent water solubility, low cytotoxicity and good photobleaching resistance. The N-CDs can be used as a fluorescent probe for the detection of Fe³⁺ ions in aqueous solutions and bioimaging in living cells.