Abstract

Squamous Cell Carcinoma (SCC) is a common type of skin cancer usually detectable in body areas exposed to UV rays of sun such as head, neck and arms. Among the methods that are proposed in order to treat cancer is Photodynamic Therapy (PDT), an innovative therapy. Critical to the effectiveness of the treatment is a chemical molecule, the photosensitizer, which via excitation produces reactive oxygen species that destroy tumor lesions. Silicon phthalocyanines have drawn the attention of the scientific community since the presence of silicon ensures the increased production of reactive oxygen species. However due to their structure, they are insoluble in aqueous solutions. Silicon phthalocyanine dichloride, SiCl₂Pc, is a hydrophobic second-generation photosensitizer showing aggregation in waterbased solutions. In order to overcome hydrophobicity, in this study, the encapsulation of SiCl₂Pc in β-cyclodextrin and hydroxypropyl-β-cyclodextrin using the kneading method was proposed. Their action as photosensitizers was assessed by photophysical, photochemical and in vitro photobiological studies against squamous cell model skin cancer A431. The Dynamic Light Scattering (DLS) method was used to determine their size, polydispersity index and z-potential, while their structural characterization was performed by Infrared Spectroscopy (FT-IR). The results of photodynamic treatment showed that the encapsulation of SiCl₂Pc into cyclodextrins improved its aqueous solubility enhancing its photodynamic action (50% cell viability for β-CD-SiCl₂Pc, 57% for HP-β-CD-SiCl₂Pc and 67% SiCl₂Pc after irradiation for 3 min with 15 mW/cm²).

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