Nanomaterials for Photodynamic Therapy in Cancer: Classifications, Recent Advances, and Combination Applications.

Photodynamic therapy (PDT) has emerged as a promising non-invasive therapeutic modality for cancer treatment. Compared with conventional antineoplastic therapies, PDT offers targeted cytotoxic effects and relatively low systemic toxicity, making it an attractive therapeutic option for patients with cancer. The therapeutic efficacy of PDT is largely determined by the intrinsic properties of photosensitizers (PSs), which are the central components of this therapeutic approach. However, currently available PSs still present several inherent limitations, including inadequate penetration into deep tumor tissues, suboptimal accumulation and delivery at tumor sites, and substantial dependence on oxygen availability within the tumor microenvironment. Consequently, the development of high-performance PSs remains a key research priority in the field of PDT. Recent advances in photosensitizer technology have enabled the rational integration of PDT with other therapeutic modalities, including radiotherapy, chemotherapy, and immunotherapy, to achieve synergistic therapeutic effects, thereby significantly improving overall treatment outcomes. This review systematically summarizes the major classifications, key characteristics, and recent advances in the application of nanomaterials for PDT. It evaluates the current progress in the development of nanomaterial-based PSs and examines their potential applications in combination therapeutic strategies for cancer treatment. Collectively, these findings provide valuable insights into the future development of PDT-based anticancer therapies.