Enhanced Antibacterial Properties Of Face Mask Decorated With Nitrogen-Doped Carbon Dots And Silver (Ncds/Agnps) Nanocomposites

Face masks have become an essential part to minimize the spread of bacteria. However, bacteria may develop on the surface of face masks and result in several health issues. The incorporation of silver nanoparticles (AgNPs) can improve the antibacterial properties of face masks. Due to the lack of easily aggregated AgNPs, surface modification with capping agents such as nitrogen-doped carbon dots (NCDs) could improve their stability, antibacterial activity, and prevent aggregation. This study aimed to investigate the antibacterial effect of face masks decorated with NCDs/AgNPs nanocomposites. Therefore, we synthesize NCDs from pineapple peel to prepare NCDs/AgNPs nanocomposites without using toxic chemicals with various AgNO3 concentrations. Face masks coated with NCDs/AgNPs nanocomposites were fabricated by using the dip-coating method at low temperatures (25oC). The antibacterial activities of treated face masks were tested against model gram-positive (Escherichia coli) and gramnegative bacteria (Bacillus subtilis). All treated face mask samples showed better antibacterial activity compared with untreated face masks from the zone of inhibition, colony counting, and inhibition ratio result. The face mask- NCDs/AgNPs 14 (AgNO3 14 mM) showed the best antibacterial properties with a 99.7% reduction of both bacteria
in the colony counting result. The OD600 study also showed the face mask-NCDs/AgNPs 14 have 98.89% and 99.78% inhibition ratio against Escherichia coli and Bacillus subtilis after 12 h. It also demonstrated the contactkilling ability of NCDs/AgNPs on the surface of the face mask from the zone of inhibition result. A higher concentration of AgNO3 in synthesizing NCDs/AgNPs results in a larger nanocomposite size. However, it can provide more antibacterial properties. Thereby, the synergistic effect of NCDs/AgNPs nanocomposites can greatly improve bacterial growth inhibition properties and show a potential to be used as antibacterial agents on face masks