The Impact of Carbon-Based Nanomaterials on Antimicrobial Photodynamic Therapy (aPDT)

Introduction: The escalating global burden of antimicrobial resistance (AMR) and persistent biofilm-associated infections has created an urgent need for novel therapeutic strategies. Antimicrobial photodynamic therapy (aPDT) has emerged as a promising, resistance-independent approach capable of generating reactive oxygen species (ROS) to damage multiple cellular targets. Methods: This review synthesizes recent advances in the application of carbon-based nanomaterials-including carbon quantum dots (CQDs), graphene quantum dots (GQDs), porphyrin-carbon hybrids, and related nanocomposites-to enhance the efficacy of aPDT against bacterial pathogens and biofilms. Results: Carbon quantum dots demonstrate potent photosensitizing properties, enabling high levels of microbial inactivation under blue light irradiation, while graphene quantum dots effectively serve as nanocarriers for hydrophobic photosensitizers, significantly improving solubility, cellular uptake, and biofilm penetration. Hybrid systems, such as N/S-doped CQDs combined with mesoporous silica or chitosan-modified carbon platforms, provide stimuli-responsive delivery and superior anti-biofilm activity. Porphyrin-encapsulated electrospun nanofibers and carbon-based nanozymes further amplify ROS generation and enable multifunctional applications, including sensing and synergistic therapies such as sonophotodynamic inactivation (SPDI). Collectively, these nanomaterials overcome key limitations of conventional aPDT by enhancing ROS production, improving biofilm disruption, and reducing required treatment parameters, while maintaining low cytotoxicity toward mammalian cells. Conclusion: Despite promising preclinical results, challenges remain in standardization, scalability, long-term biosafety, and clinical translation. This review highlights the transformative potential of carbon-based nanomaterials in revolutionizing aPDT and outlines future directions to accelerate their development into effective tools against resistant infections and biofilms.