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.