Carbon nanodots (CNDs) have been studied in the field of biomedicine, such as drug delivery, bioimaging and theragnosis because of their superior biocompatibility and desirable optoelectronic properties. However, limited assessments on the biological effects of CNDs, particularly the effect on oxidative stress in living cells, are not adequately addressed. In this work, nitrogen-doped (N-CNDs) or nitrogen sulfur-doped CNDs (N,S-CNDs), which were found to have strong antioxidant capacity in free radical scavenging in physicochemical conditions, have been investigated through measuring the fluctuations of the intracellular reactive oxygen species (ROS), such as the hydrogen peroxide and superoxide anion, at different dose ranging from 0.05 – 0.80 mg/mL exposure in two cell lines, EA.hy926 and A549 cells. The N-CNDs present consistent antioxidant capacity as in physicochemical testing and low-cytotoxicity to both cell lines. In contrast, the treatment of the N,S-CNDs induces the significant production (raising by &gt;30% at 0.8 mg/mL) of intracellular ROS level measured by H2O2 and O2-, causing oxidative stress and deleteriousness to both cell lines at the viability of ~50% evaluated by MTT (3-(4,5- dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. These results suggest that the sulfur-containing components in CNDs play an important role on the oxidative stress responses in the cells. The mitochondrial membrane potential of the cells was monitored upon the N,S-CNDs treatment and found to increase monotonically with the concentration of the N,S-CNDs, corresponding to the ROS generation. It is proposed that the N,S-CNDs, most likely the sulfur-bearing bonds and/or functional groups in the CNDs, stimulate ROS generation by modulating the electron transport chain in the mitochondrial membrane.

Carbon nanodots in living cells: Effect on oxidative stress and cytotoxicity

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.