Photodynamic inactivation of prions by disulfonated hydroxyaluminium phthalocyanine

Sulfonated phthalocyanines (Pcs) are cyclic tetrapyrroles that constitute a group of photosensitizers. In the presence of visible light and diatomic oxygen, Pcs produce singlet oxygen and other reactive oxygen species that have known degradation effects on lipids, proteins and/or nucleic acids. Pcs have been used successfully in the treatment of bacterial, yeast and fungal infections, but their use in the photodynamic inactivation of prions has never been reported. Here, we evaluated the photodynamic activity of the disodium salt of disulfonated hydroxyaluminium phthalocyanine (PcDS) against mouse-adapted scrapie RML prions in vitro. PcDS treatment of RML brain homogenate resulted in a time- and dose-dependent inactivation of prions. The photodynamic potential of Pcs offers a new way to inactivate prions using biodegradable compounds at room temperature and normal pressure, which could be useful for treating thermolabile materials and liquids.

Morphology and radical reactions of Cu(II) and Co(II) sulfonated phthalocyanines covalently linked to poly(ethyleneamide)

The tetrasulfonated Cu II( tspc )4-, tspc = 4,4′,4″,4‴-phthalocyaninetetrasulfonate, and the trisulfonated Co II( trspc )3-, trspc = n , n ′, n ″-phthalocyanine-trisulfonate and n, n′ and n″ indicate the sulfonated positions of the various isomers, were covalently linked to a polyethyleneimine, M n ~ 10000 and M w ~ 25000, backbone. A fraction of the amine groups in a strand was converted to Cu II pc (- SO 3)3(- SO 2 N <)\3- or Co II pc (- SO 3)2(- SO 2 N <)\2- pendants and the remaining were acetylated. Strands of the polymers, poly(K3CuIItspc) and poly(K2CoIItrspc) , formed spherical bundles with diameters ~1000 nm for poly(K3CuIItspc) and ~100 nm for poly(K2CoIItrspc) . The stability of the bundles is metal-dependent. Poly(K2CoIItrspc) forms the most stable bundles with respect to hydrolytic and redox reactions. ESR and optical spectroscopies as well as reactions of the pendants with pulse radiolytically generated radicals, namely e - sol , C•H2OH, (CH3)2COHC•H2 , CO 2•-, N 3• and SO 4•-, revealed a distribution of pendants between isolated and aggregated forms in a bundle. The reduction of the Cu(II) to Cu(I) in aqueous solutions of the poly(K3CuIItspc) was associated with pendants present in a mostly hydrophobic environment. Unstable phthalocyanine pendants with CoIII -carbon bonds are formed when CoIIpc(-SO3)2(-SO2N<)\2- reacted with C -centered radicals, ( CH3)2COHC•H2 and C•H2OH . The species with CoIII -carbon bonds were precursors to the formation of CoIpc(-SO3)2(-SO2N<)\3- pendants. The redox reactions of the pendants in these polymers are compared with those of K4CuIItspc and K3CoIItrspc .