Phthalocyanines as Promising Tools in Photodynamic Therapy and Biological Applications

The development of photosensitizers with enhanced photodynamic activity and broad-spectrum applicability is crucial for antimicrobial and anticancer therapies. This study explores the potential of novel anionic phthalocyanines in overcoming microbial resistance and combating melanoma. The photophysical properties of phthalocyanines were evaluated, including singlet oxygen quantum yields (ΦΔ) and photostability. Photodynamic inactivation assays were conducted against pathogens, including multidrug-resistant strains, and melanoma cell viability was assessed following photodynamic therapy (PDT). Synergistic effects with doxycycline were also investigated. Phthalocyanines exhibited high ΦΔ and retained photodynamic efficacy against pathogens even at low concentrations. Synergistic effects with doxycycline were observed against MRSA and E. coli (ESBL+). In melanoma studies, the most active PS reduced cell viability by 85% after 1 hour of irradiation. The studied phthalocyanines demonstrated strong potential for antimicrobial and anticancer PDT, especially as adjuvants in combination therapies.