Biomimetic Synthesis of Carbon Dots from Mimosa pudica Leaves for Enhanced Bioimaging

Eco-friendly nitrogen doped carbon dots (ENCDs) was obtained by hydrothermal carbonization method from the leaves extract of Mimosa pudica. ENCDs were found to possess unique optical properties with a blue emission at 400 nm. ENCDs were evenly distributed on the copper grids for HR-TEM analysis and were found to be of similar to 3 nm in size. SAED patterns and broad XRD peaks with (002) and (100) planes showed their amorphous nature. Functional moieties present in ENCDs were explained from the FTIR data. XPS and EDS data confirmed the presence of. C (65.81%), N (11.01%) and O (23.19%) atoms and their relative proportion in ENCDs. Zeta potential studies revealed that the resulting ENCDs possess a negative zeta potential (-20.6 mV) confirming their stability. MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay) explained that ENCDs were less toxic to the HeLa cells even at a concentration of 100 mu g/ml. A strong fluorescence of ENCDs were noticed at different excitation wavelengths in the in-vitro bio-imaging of HeLa cells. Finally, owing to the multicolor fluorescence emission ability and less cytotoxicity, ENCDs could be applied to real biological fluorescent applications in future.