Developing zinc oxide and peanut shell-derived carbon star-shaped composite materials for effective...

The development of new carbon-based materials using natural biowaste for biomedical applications has remained a significant challenge in the past decades. In this study, we successfully synthesized and characterized composite materials made from peanut shell-derived carbon (PNS-C) decorated on ZnO that formed star-shaped particles via a simple hydrothermal technique. The as-prepared composites possess several advantages, including unique optical properties and high photostability. We evaluate the antibacterial performance against Escherichia coli, a gram-negative bacterium and Staphylococcus aureus, a gram-positive bacterium, under irradiated and non-irradiated conditions. Interestingly, the photo-antibacterial activities of ZnO/PNS-C composites showed great inhibition of bacterial growth as compared to pure ZnO. Moreover, significant disruptions in cellular activities occur when the composites make direct contact with the bacterial cell wall. The electrons and holes produced by excitation in composites provide a pronounced deactivating effect on bacterial activity. In addition, ZnO/PNS-C composites are highly biocompatible with normal cells. Thus, these newly developed composites made from a natural biowaste system with an affordable price, abundance, and non-toxicity could provide a potentially environmentally friendly and fruitful route for antibacterial therapy in future applications.