Fullerenol spin probe containing isoindoline nitroxide and porphyrin groups

Abstract

ABSTRACTA water-soluble fullerenol containing porphyrin and isoindoline nitroxide groups APTSPP-C60(OH)10-(TMIO)3 was synthesized by the incorporation of 5-(4-amino-phenyl)-10,15,20-tris(4-sulfonatophenyl)-porphyrin (APTSPP) as a tumor-targeting group and 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO) into fullerenol C60(OH)11. This nonmaterial was further characterized by FT-IR, UV, MS, TEM, fluorescence, etc. and its properties in vitro were also evaluated. Electrochemical experiments indicated that APTSPP-C60(OH)10-(TMIO)3 retained similar electrochemical properties and redox reaction mechanisms as 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO). Electron paramagnetic resonance (EPR) spectra of APTSPP-C60(OH)10-(TMIO)3 exhibited the hyperfine splittings and characteristic spectra of CTMIO, with typical nitroxide g-values and nitrogen isotropic hyperfine coupling constants. In vitro cytotoxicity assay showed APTSPP-C60(OH)10-(TMIO)3 possessed low cytotoxicities to human renal tubular epithelial 293T cells and HepG-2 cells. Therefore APTSPP-C60(OH)10-(TMIO)3 may be considered as a potential candidate for novel biological spin probe using EPR spectroscopy.