[Dynamic phototherapy: study of anti-tumour potentialities of bis (tri n-hexylsiloxy) silicon phthalocyanine on malignant achromic M6 melanocytes. EPR study of phototoxic mechanism].

Photodynamic therapy of cancerous cells is a technique relying upon the irradiation of tumorous cells after selective incorporation of a photosensitizer. The bis (tri n-hexylsiloxy) silicon phthalocyanine is a second generation photosensitizer. Anti-cancerous potentialities of this molecule have been evaluated against the melanotic M6 cell line. Results have evidenced a high phototoxicity at low concentration and no dark toxicity under the same conditions. EPR studies on the photochemical pathways involved in phototoxicity processes have been realised in solvent and model membranes (liposomes). Results provide evidences for the production of singlet oxygen (1O2) as well as superoxide (02(o)-) and hydroxyl radicals (0OH).