Opportunities and challenges of metal phthalocyanines composites in photodynamic therapy as photosensitizers: A comprehensive review

Photodynamic therapy (PDT) is a promising treatment for various diseases, including cancer cell development, contamination, and microbial infections. Metal phthalocyanines (MPcs) have emerged as prominent photosensitizers (PSs) for PDT owing to their chemical and photophysical properties and ease of functionalization. This comprehensive review explores the opportunities and challenges of MPc and their crucial role in generating reactive oxygen species upon light activation, which induces cytotoxic effects in targeted cells. We examined the photophysical properties of MPc, their action in PDT, and their suitability parameters, such as solubility, biodistribution, and selectivity for diseased tissues. To extend PDT feasibility, we examined recent advancements in the design and synthesis of MPc composites, including their integration into nanocarriers and functionalization with targeting ligands. These innovations aim to enhance PDT specificity and efficiency while minimizing off-target effects. Additionally, this review compares MPc-based PDT to conventional therapies, highlighting its potential application as an advanced approach to enhancing PDT activity. Finally, this study identifies the future research directions and technological innovations necessary to optimize the clinical translation of MPc composites in PDT, highlighting their current state and prospects as PSs and emphasizing their role in advancing PDT as a targeted and effective therapeutic approach in modern medicine.