Single step synthesized sulfur and nitrogen doped carbon nanodots from whey protein: nanoprobes for longterm cell tracking crossing the barrier of photo-toxicity

Abstract

Long-term cell tracking is a research interest for biological scientists across disciplines and applications. However, long-term cell tracking experiments are often limited due to photobleaching and phototoxicity. In the current study, a carbonaceous nanoprobe was developed using a single step microwave assisted degradation of whey protein in the aqueous phase. The CNDs were characterized via UV-Vis spectroscopy, fluorescence spectroscopy, HRTEM, DLS and FTIR. Due to choice of the precursor, the CNDs were observed to be doped with sulfur and nitrogen. The CNDs were capable of bioimaging. In a 2D cell culture system (culture flask), the cells retained fluorescence for up to five passages. In a 3D microenvironment, cell tracking was also successful for up to 10 days. The CNDs were observed to be capable of scavenging superoxides and hydroxyl radicals in vitro. The CNDs were also observed to save cells from phototoxicity and UV exposure via cytotoxicity, microscopy and nanoindentation analysis.