Multifunctional PDA-graphene family nanocomposites for antibacterial and anticancer photothermal therapy

The increasing demand for multifunctional, biocompatible nanomaterials has spurred the exploration of hybrid systems with synergistic antimicrobial, anticancer, antioxidant, and regenerative properties. In this study, polydopamine (PDA)-based nanocomposites incorporating graphene oxide (PDA-GO) and graphene quantum dots (PDA-GQD) were synthesized and systematically characterized for their physicochemical and biological functionalities. The nanocomposites raised temperature > 50 °C within 5 min under 808 nm laser irradiation (1.5 W/cm², 250 μg/mL). Both composites showed antibacterial activity against Escherichia coli (E. coli) (Gram-negative) and Staphylococcus aureus (S. aureus) (Gram-positive), achieving >99 % bacterial eradication under 10 min NIR irradiation at 125 μg/mL, indicating a combined photothermal (PT) and oxidative mechanism. In parallel, in vitro cytotoxicity assays revealed selective toxicity toward MCF-7 cancer cells-reducing viability to 95 % viability of normal L929 fibroblasts. Antioxidant assays confirmed >80 % DPPH radical scavenging at 250 μg/mL, supporting their potential in oxidative stress modulation. Furthermore, scratch wound healing assays demonstrated ∼100 % wound closure within 48 h in NIR-irradiated PDA-GO/PDA-GQD groups. Intracellular H₂O₂ generation reached up to 30.5 μM in MCF-7 cells under laser, enabling dual PT-photodynamic (PD) therapy. Altogether, these findings position PDA-GO and PDA-GQD nanocomposites as versatile platforms for integrated antibacterial, anticancer, and wound-healing therapies, highlighting their promise for future biomedical applications beyond conventional monofunctional approaches.