Phthalocyanine-nanoparticle conjugates for enhanced cancer photodynamic therapy

Photodynamic therapy (PDT) represents a selective and minimally invasive strategy for cancer treatment, relying on light-activated photosensitizers (PSs) to produce ROS that induce tumor cell death. Among various PSs, phthalocyanines have emerged as promising candidates owing to their strong absorption in the near-infrared region, excellent photostability, and high singlet oxygen quantum yield. However, their clinical application remains limited by poor water solubility, tendency to aggregate, and insufficient tumor specificity. To address these challenges, nanoparticle-based delivery systems have been extensively explored to enhance the performance of phthalocyanine (Pc) photosensitizers. This review specifically highlights the integration of metallophthalocyanines (MPcs) with a range of nanoparticles (NPs), including gold, silver, titanium dioxide, magnetic NPs and polymeric carriers. It provides a comprehensive overview of key advancements from 2023 to 2025 in nanoparticle-mediated delivery strategies for phthalocyanine-based PSs in cancer photodynamic therapy. These nanostructures not only improve the solubility and stability of MPcs but also facilitate targeted delivery and enhance photodynamic efficacy through better cellular uptake and controlled release mechanisms. Different classes of nanocarriers and their design strategies for optimizing therapeutic outcomes are critically discussed. Furthermore, the review addresses current challenges such as biological barriers, potential toxicity, and regulatory considerations. Future perspectives on clinical translation are also explored, emphasizing the significant potential of nanoparticle-assisted MPc systems to revolutionize cancer photodynamic therapy.