Versatile Gold-Coupled Te-Carbon Dots for Quantitative Monitoring and Efficient Scavenging of Superoxide Anions

The superoxide anion (O2 •–) is a reactive oxygen species (ROS) that functions as an important regulator of signal transduction in living systems. However, excess O2 •– can cause metabolic imbalances and oxidative damage inside cells. Quantitative detection and efficient scavenging of O2 •– are therefore critical for maintaining intracellular redox balance and homeostasis. In this work, a nanomaterial (Au-TeCD) composed of BSA-modified gold nanoparticles (AuNPs) complexed with tellurium-containing carbon dots (TeCDs) was constructed. The introduction of Au-TeCDs to solutions containing superoxide resulted in enhanced elimination of the anion, indicating that Au-TeCDs are able to scavenge O2 •– from the surrounding environment. Notably, the respective TeCD and AuNP components of the Au-TeCDs were found to emit fluorescence at 425 and 640 nm upon exposure to superoxide anions. This unique spectroscopic property of Au-TeCDs allowed levels of O2 •– in solution to be quantified using dual-fluorescence detection. The Au-TeCDs developed herein also exhibited low-cytotoxicity, versatile capabilities for in situ fluorescence imaging, and effective scavenging of O2 •– in living cells. Taken together, these results suggest that Au-TeCDs act as effective tools for monitoring superoxide concentrations in complex mixtures and may be developed as possible therapeutics designed to scavenge excess ROS from diseased cells.