Biologically active dual functional zinc-doped biomass-derived carbon dots†

The resistance of bacteria to antibiotics poses a significant challenge in the current global landscape. Despite this urgency, the pace of drug development has not matched the pressing need. Addressing this gap, we have developed zinc-doped carbon dots (Zn-Cdots) using biomass as a carbon source by a simple, and eco-friendly hydrothermal method to treat bacterial infection. Plant-derived biomass serves as an excellent source of various bioactive molecules, making it a viable carbon source for synthesizing Zn-Cdots. The characterization of Zn-Cdots was performed using multiple techniques, including UV-Visible spectroscopy, photoluminescence spectroscopy, TEM analysis, XRD, FTIR and XPS. The Zn-Cdots exhibit superior antibacterial properties in combating Gram-negative and Gram-positive bacterial strains, specifically Serratia marcescens and Staphylococcus aureus compared to the precursor biomass extract. Additionally, ROS measurements revealed the antioxidant property of Zn-Cdots, while agarose gel electrophoresis studies confirmed that the interaction between pDNA and Zn-Cdots heightened the antibacterial activity of Zn-Cdots. Moreover, the ABTS assay and the TMB assay both validated the antioxidant activity of Zn-Cdots, revealing high efficacy in scavenging free radicals and further highlighting its potential in mitigating oxidative stress alongside potent antibacterial efficacy.