Size tunable fluorescent nano-graphite oxides: preparation and cell imaging applications.

Fluorescent nano-graphite oxides (NGO) with different size distribution were prepared via a one-pot hydrothermal route using ultrasmall graphite powder as starting material and subsequently separated using dialysis tubes with different molecular weight cutoff. The biomedical applications of these NGO for cell imaging were further investigated. Fourier transform infrared spectra demonstrated that many functional groups including the hydroxyl group, carboxyl group and epoxy group were present on NGO, which endowed them with good water solubility. These NGO showed size-dependent photoluminescence and excellent biocompatibility with A549 cells. As evidenced by laser scanning confocal microscopy images, NGO could be internalized by A549 cells and located in the cytoplasm. Given their good water solubility, size tunable photoluminescence and excellent biocompatibility, these NGO should be promising for bioimaging and various biomedical applications.