Green synthesis of carbon dots from rose-heart radish and application for Fe3+ detection and cell imaging

Herein, a simple, green, and low-cost way was developed in the synthesis of fluorescent carbon dots (CDs) with well-distributed size, using one-pot hydrothermal treatment of rose-heart radish. The as-prepared carbon dots exhibit exceptional advantages including high fluorescent quantum yield (13.6%), excellent biocompatibility, low-toxicity, and satisfactory chemical stability. More strikingly, as-synthesized N-CDs generate strong response to Fe3+ ions and gives rise to the fluorescence quenching. This phenomenon was used to develop a fluorescent method for facile detection of Fe3+ with a linear range from 0.02 to 40 μM and a detection limit of 0.13 μM (S/N = 3), and further extended to measure environmental water samples with satisfactory recoveries. Eventually, the low toxicity and strongly fluorescent carbon dots were applied for cell imaging and the quenched fluorescence by adding Fe3+, demonstrating their potential towards diverse applications.