Silicon phthalocyanines for photodynamic therapy studies

Four sulfonated silicon phthalocyanines SiPc(1-SO3H)[OSi( n-C6H13)3]2, 2 , Pc 177; SiPc(2-SO3H)[OSi(n-C6H 13)3]2, 4, Pc 178; SiPc(1-SO 3H)[OSi(CH3)2(CH2)3N(CH 3)2]2, 3, Pc 179; and SiPc(2-SO 3H)[OSi(CH3)2(CH2)3N(CH 3)2]2, 5, Pc 180, were prepared and characterized. The first two were made for an abandoned external study and the second two for an internal photodynamic therapy (PDT) study. In further work, acid SiPc[OSi(CH3)2(CH2)10C(O)OH] 2, 28, Pc 61 was prepared and was conjugated with trimer H(C9H10N2O2)3OCH 3, 15, a trimer first synthesized by Hamilton. This trimer has the potential to bind to Bcl-2 and Bcl-xL proteins (proteins which are overexpressed in cancer cells). The two conjugates obtained, SiPc[OSi(CH 3)2(CH2)10C(O)(C9H 10N2O2)3OCH3]2, 30, Pc 212; and HOSiPcOSi(CH3)2(CH2) 10C(O)(C9H10N2O2)3 OCH3, 31, Pc 213, have the potential to complex with the Bcl-2 and Bcl-xL through their aminotrimer units and with photodynamic action to destroy these proteins and their associated cancer cells. Also, two alkyl silicon phthalocyanines, HS(CH2)3SiPcOSi(CH 3)2(CH2)3N(CH3)2, 52, Pc 227; and CH3S(CH2)3SiPcOSi(CH 3)2(CH2)3N(CH3)2, 58, Pc 223, were prepared as "masked Pc 4s". These two alkyl phthalocyanines have the potential to bind to Au nanoparticles through their SH and SCH3 functional groups respectively. The phthalocyanine-Au nanoparticle conjugates appear to have the potential to target tumor tissues, and when irradiated with red light in the presence of H2O and O 2 to yield Pc 4. Pc 4 has the ability to destroy the tumor tissues when used in PDT.