In Vitro Phototoxicity of Liposomes and Nanocapsules Containing Chloroaluminum Phthalocyanine on Human Melanoma Cell Line

In this study, the photodynamic action of liposomes (LP) and nanocapsules (NC) containing Chloroaluminum phthalocyanine (ClAlPc), on the human melanoma cell (WM 1552C), was assessed. The light source was setup at 672 nm, which corresponds to the maximum absorption wavelength of the ClAlPc. Both colloidal carriers presented size in nanometric scale as well as negative zeta potential. The cellular damage was light dose dependent ranging from 30% of cell death at 70 mJ · cm⁻² to 90% of death at 700 mJ · cm⁻². However, the photocytotoxic effect of LP at 70 mJ · cm⁻² was slightly more efficient to induce cellular death than NC formulation. At 140 mJ · cm⁻², and 700 mJ · cm⁻² both nanocarriers were equally efficient to induce cellular damage. Therefore, in the present work, the maximum phototoxic effect was obtained with 700 mJ · cm⁻² of light dose, in combination with 0.29 μg · mL⁻¹ of ClAlPc encapsulated into LP and NC. The cells were also positive to annexin V, after the PDT treatment with LP and NC, showing that one of the mechanisms of cellular death involved is apoptosis. In summary, the potential of LP and NC as a drug delivery system, in Photodynamic Therapy (PDT) against melanoma, has been confirmed using a lower concentration of the photosensitizer and lower light doses than that applied in current protocols. This is an innovative proposal to treat melanoma cell lines that until now have not received the benefit of the PDT protocol for treatment.