Luminescent carbon quantum dots and their application in cell imaging

A facile hydrothermal method was used to synthesize luminescent carbon dots from single-walled carbon nanotubes (SWNTs). Then 4,7,10-trioxa-1,13-tridecanediamine (TTDDA) was grafted onto the carbon dots to increase their water solubility and luminescent properties. The as-prepared carbon dots were characterized by UV-Vis absorption, infrared (IR), Raman, fluorescence, and transmission electron microscopy (TEM). The results confirmed that these carbon dots were monodispersed in water and emitted bright yellow fluorescence. The surface modified carbon dots were used to label biological cells, and the images obtained by a laser scanning confocal microscope showed that the carbon dots were gradually taken up by HeLa cells. The cytotoxicity of such carbon dots toward HeLa cells was very low, for 24 h the LC 50 was over 5 mg mL 1 . Yellow-emitting monodispersed carbon nanoparticles (CNs) were synthesized from single-walled carbon nanotubes (SWCNTs) and modified with an amine (TTDDA), which exhibited good biocompatibility toward HeLa cells and produced bright cellular images under a confocal laser microscope.