A hydrothermal reaction of an aqueous solution of BSA yields highly fluorescent N doped C-dots used for imaging of live mammalian cells.

In the current study, we present a new and facile synthesis of N doped C-dots (N@C-dots) by hydrothermally reacting an aqueous solution of Bovine Serum Albumin (BSA). The as-prepared quantum dots (QDs) exhibited high quantum yield (44%), high photostability, colloidal stability, and high functionalization efficiency. In addition to their low cost, the N@C-dots have demonstrated a non-toxic and long-lasting effect when applied for imaging human cells (human osteosarcoma U2OS cells). Importantly, with high physiological stability, excellent biocompatibility, and homogenous distribution, the N@C-dot suspension was exploited for high quality cell imaging and to model the biological effects at the nuclear level. Moreover, the water-soluble N@C-dots are nontoxic to the selected cell line in our preliminary evaluation.