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Three fullerene isoindoline nitroxides N-methyl-3,4-fulleropyrrolidine-2-spiro-5′- (1′,1′,3′,3′-tetramethylisoindolin-2′-yloxyl), (C60-(TMIO)m, and C70-(TMIO)n) were synthesized by the covalent bonding of 5-formyl-1,1,3,3-tetramethyl isoindolin-2-yloxyl to the fullerenes C60and C70. Significantly, the X-ray photoelectron spectra indicated the characteristic N 1s signals of NO.at 402 eV. The atomic force microscope morphologies showed that the average particle sizes of C60-(TMIO)mand C70-(TMIO)nwere 38 and 15 nm. The electrochemical experiments indicated that fullerene bound isoindoline nitroxides retained similar electrochemical properties and redox reaction mechanisms as the parent nitroxides. The electron paramagnetic resonance spectra of the fullerene isoindoline nitroxides all exhibited the hyperfine splittings and characteristic spectra of tetramethyl isoindoline nitroxides, with typical nitroxide g-values and nitrogen isotropic hyperfine coupling constants. Therefore, these fullerene isoindoline nitroxides may be considered as potential candidates for novel biological spin probes using electron paramagnetic resonance spectroscopy. [ABSTRACT FROM PUBLISHER]

The multi-modal imaging contrast agent has been attracted an increased interest to the tumor detecting and diagnosis in these recent years since the multi-modal imaging technology combines the advantages of several medical imaging modalities. A water-soluble fullerenol probe containing glypican-3 monoclonal antibody (GPC3-mAb) group mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 was synthesized by the incorporation of 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO), naphthalimide (NI) and GPC3-mAb as a tumor-targeting group into fullerenol C60(OH)11. This nanomaterial was further characterized by FTIR, UV, MS, fluorescence, etc., and then its properties including electron paramagnetic resonance (EPR), particle size, electrophoresis, electrochemical assay, cell cytotoxicity, cell uptake and fluorescent imaging of HeLa tumor cells in vitro were also evaluated. Experiment results indicated that mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 had similar fluorescent properties as NI and similar electrochemical and redox properties as 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO). Moreover, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 possessed low cell cytotoxicity, good fluorescence and good tumor-targeting property. Meanwhile, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 can be taken up highly by HeLa tumor cells, achieve good green fluorescent imaging in tumor cells and highly enhance the contrast of fluorescent images. Therefore, mAb-GPC3-C60(OH)10-(TMIO)3-(NI)3 can disperse homogeneously in aqueous solution and be used as a potential tumor-targeting dual-modal contrast agent for EPR imaging/fluorescence imaging (EPRI/FI). [ABSTRACT FROM AUTHOR]

A water-soluble fullerenol containing porphyrin and isoindoline nitroxide groups APTSPP-C60(OH)10-(TMIO)3was 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)3retained 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)3exhibited 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)3possessed low cytotoxicities to human renal tubular epithelial 293T cells and HepG-2 cells. Therefore APTSPP-C60(OH)10-(TMIO)3may be considered as a potential candidate for novel biological spin probe using EPR spectroscopy. [ABSTRACT FROM AUTHOR]