Facile synthesis of nitrogen-doped carbon dots for Fe3+ sensing and cellular imaging

A fast and facile approach to synthesize highly nitrogen (N)-doped carbon dots (N-CDs) by microwave-assisted pyrolysis of chitosan, acetic acid and 1,2-ethylenediamine as the carbon source, condensation agent and N-dopant, respectively, is reported. The obtained N-CDs are fully characterized by elemental analysis, transmission electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction pattern, X-ray photoelectron spectroscopy, UV-vis absorption, and photoluminescence spectroscopy. Doping N heteroatoms benefits the generation of N-CDs with stronger fluorescence emission. As the emission of N-CDs is efficiently quenched by Fe3+, the as-prepared N-CDs are employed as a highly sensitive and selective probe for Fe3+ detection. The detection limit can reach as low as 10 ppb, and the linear range is 0.010-1.8 ppm Fe3+. The as-synthesized N-CDs have been successfully applied for cell imaging and detecting Fe3+ in biosystem. (C) 2014 Elsevier B.V. All rights reserved.