Recent Progress on Carbon Dots for Tumor Photodynamic Therapy

Carbon dots (CDs), as a burgeoning class of zero-dimensional carbon-based nanomaterials, have garnered significant attention in biomedicine due to their various advantages. While extensive studies have focused on their fluorescence and photothermal characteristics, their potential as advanced photosensitizers for photodynamic therapy (PDT) is increasingly recognized. This review provides a systematic and focused summary of recent advances in CD-based tumor PDT. Design strategies for CDs with photodynamic properties are comprehensively categorized, with the donor-acceptor strategy highlighted as the first-ever summary of this rational approach. By improving tumor targeting, alleviating hypoxia, and depleting overexpressed glutathione, the unfavorable tumor microenvironment for CD-based PDT can be effectively circumvented. To overcome the limitations of monotherapies, CD-based PDT is often integrated with photothermal therapy, chemotherapy, and immunotherapy, particularly in combination with immunogenic cell death and immune checkpoint blockade therapy. Such synergistic strategies enable effective eradication of primary tumors while simultaneously establishing long-term immune surveillance against circulating tumor cells. Furthermore, by integrating imaging guidance with therapeutic function, imaging-guided CD-based PDT offers a theranostic platform that paves the way for precise tumor therapy. Collectively, this review offers a comprehensive roadmap for the rational design and translational development of CD-based PDT.