Multifunctional sensing applications of biocompatible N-doped carbon dots as pH and Fe3+ sensors

Abstract Recently, carbon dots (CDs) with long wavelength (i.e., orange and red-light) are gradually critical in the bioimaging and biomedical fields. In this paper, a simple one-pot hydrothermal method for preparing bright orange N-doped carbon dots (N-CDs) from p -phenylenediamine has been developed. The resulting N-CDs with abundant surface functional groups show strong orange fluorescence, certain water solubility property and obvious fluorescence quenching to Fe 3+ ions and pH. What's more, the fluorescence of the N-CDs displays a consequent color variation with the increasing concentration of Fe 3+ and pH. In short, N-CDs can be considered as an efficient and multifunctional fluorescent sensor for monitoring pH and Fe 3+ because of their prominent biocompatibility and low toxicity characteristics.