Self-assembled phthalocyanine-based nano-photosensitizers in photodynamic therapy for hypoxic tumors

Photodynamic therapy (PDT) is a well-established minimally invasive cancer treatment, yet its effectiveness in treating hypoxic tumors is limited due to oxygen scarcity, hindering the production of reactive oxygen species (ROS). Phthalocyanines, notable for their remarkable optoelectronic attributes and structural flexibility, have emerged as a class of photosensitizers with potential to enhance PDT. This review highlights innovations in the development of self-assembled phthalocyanine-based nano-photosensitizers, underscoring their potential to mitigate the obstacles posed by hypoxia in PDT. It details advancements in self-assembly methodologies and their applications to augment the therapeutic impact of PDT in hypoxic tumors, encompassing oxygen supply augmentation, metabolic pathway modulation, development of phthalocyanine-based nano-photosensitizers for photothermal therapy (PTT), type I PDT photosensitizers and combination therapy. It concludes with an overview of the current challenges and future prospects of phthalocyanine-based nano-photosensitizers in PDT. By reviewing recent progress, this paper aspires to offer pioneering insights into the conception of novel nano-photosensitizers, engineered to counteract hypoxia and circumvent the intrinsic limitations of PDT.