Tailoring photosensitive ROS for advanced photodynamic therapy

Photodynamic therapy (PDT) has been considered a noninvasive and cost-effective modality for tumor treatment. However, the complexity of tumor microenvironments poses challenges to the implementation of traditional PDT. Here, we review recent advances in PDT to resolve the current problems. Major breakthroughs in PDTs are enabling significant progress in molecular medicine and are interconnected with innovative strategies based on smart bio/nanomaterials or therapeutic insights. We focus on newly developed PDT strategies designed by tailoring photosensitive reactive oxygen species generation, which include the use of proteinaceous photosensitizers, self-illumination, or oxygen-independent approaches. While these updated PDT platforms are expected to enable major advances in cancer treatment, addressing future challenges related to biosafety and target specificity is discussed throughout as a necessary goal to expand the usefulness of PDT. Photodynamic therapy: Bringing light into tumors to treat cancer Advancements in photosensitive proteins, nanomaterials, and luminescence are improving the ability of photodynamic therapy (PDT) to attack cancerous tumors. In PDT photosensitive drugs are introduced into tumors, which are then exposed to light, producing reactive oxygen species that kill cells. Young-Pil Kim and coworkers at Hanyang University in Seoul, South Korea, reviewed the challenges of PDT, including drug side effects and how to deliver light into tumors. They highlight advances in protein-based photosensitive drugs, which avoid the side effects of their non-protein counterparts, and could even be generated within the body through genetic manipulation. Bioluminescent and chemiluminescent chemicals have been incorporated into nanomaterials such as quantum dots, carrying light deep into tumors. The use of hybrid oxygen-carrying proteins can provide oxygen for PDT, even inside oxygen-poor tumors that have depleted the local blood supply.