Papaya-Derived Carbon-Dot-Loaded Fluorescent Hydrogel for NIR-Stimulated Photochemotherapy and Antibacterial Activity

The improper use of antibiotics results in the emergence of drug-resistant microbes which is a serious concern to public health. Here, an NIR-stimulated fluorescent antibacterial gel has been formulated by encapsulating papaya leaf-derived carbon dots (PCQDs) in a thermosensitive PVA-melamine hydrogel. This antibacterial gel can release anticancer drug 5-Fu in a spatiotemporal and dosage controlled manner under the exposure of a 980 nm NIR laser. PCQDs can precisely generate the photothermal effect and reactive oxygen species (ROS) under NIR which induce a significant antibacterial activity in both Gram-positive and Gram-negative bacteria in a controlled manner. At the same time, a customized delivery of 5-Fu minimizes the side effect of the drug. Consequently, this innovatively designed fluorescent gel exhibited an antimicrobial effect and can act as a promising material for the NIR-responsive release of anticancer drug 5-Fu as demonstrated in B16F10 melanoma cells.