Expanding the Horizons of Phototherapy: A Review on the Superior Performance of Chalcogen-Based Photosensitizers and Photothermal Agents for Cancer Therapy

Abstract

Phototherapy, encompassing photodynamic therapy (PDT) and photothermal therapy (PTT), presents a promising cancer treatment strategy with high spatial specificity and minimal invasiveness. Optimizing these techniques hinges on the design of high-performance photosensitizers (PSs) and photothermal agents (PTAs). Single-atom chalcogen substitution, at both endocyclic and exocyclic positions in conventional organic chromophores, has proven to be a novel strategy for enhancing their photophysical and photochemical properties. Ideal PSs/PTAs exhibit high biocompatibility, visible-to-near-infrared (vis–NIR) absorption, efficient triplet state harvesting, and feasible heat and energy transfer efficiency. Moreover, chalcogen-based PSs/PTAs show promise for synergistic multimodal therapies, integrating imaging and treatment. This review comprehensively examines recent advancements (within the last five years) in utilizing chalcogen substitution to design robust PSs/PTAs for PDT/PTT. It provides a holistic perspective on spectroscopic characterization and computational analyses, singlet-oxygen/triplet quantum yields, heat generation efficiency, and in vitro/in vivo biological evaluations of chalcogen-substituted PSs/PTAs. It is anticipated that this review will stimulate further research endeavors in this promising area.