Optimizing photodynamic therapy: Talaporfin-encapsulated silica nanoparticles for red blood cell disruption in cancer treatment

Photodynamic therapy (PDT) is a highly effective cancer treatment that combines a photosensitizer (PS), and light for targeted cancer cell destruction in present of oxygen. However, the delivery of photosensitizers remains a challenge due to degradation risks and systemic toxicity. This study investigates the encapsulation of Talaporfin, a second-generation chlorin-based photosensitizer, within silica nanoparticles (SiNPs) to enhance PDT efficacy and safety. The research focuses on using red blood cells (RBCs) as a model system, highlighting their critical role in the tumor microenvironment. By targeting and destroying RBCs in proximity to tumors, PDT can disrupt the oxygen supply, indirectly leading to cancer cell death. Talaporfin-encapsulated SiNPs (T-SiNPs) were synthesized via a microemulsion method and characterized for size, morphology, and stability. The photodynamic effects of encapsulated versus naked Talaporfin were evaluated under varying concentrations and light exposure times. Results revealed that T-SiNPs achieved higher therapeutic efficacy, requiring lower concentrations and shorter exposure durations. This enhanced performance is attributed to improved light absorption and ROS production due to reduced aggregation of Talaporfin within SiNPs. Additionally, mathematical equations were developed to correlate the concentrations of encapsulated and naked Talaporfin with the 50% mortality rate (t₅₀) of RBCs. These equations provide a predictive framework for optimizing PDT protocols, enabling the determination of optimal drug concentrations and exposure times without extensive experimental trials. This study underscores the potential of silica nanoparticles as efficient carriers for photosensitizers, enhancing PDT outcomes by targeting both RBCs and cancer cells. The findings pave the way for innovative cancer therapies that leverage nanotechnology to achieve precise, effective, and safer treatments. Future applications of this approach may extend to broader therapeutic areas, further revolutionizing modern medicine.