Water-soluble fullerene (C60)N-vinylpyrrolidone copolymers were prepared by the radical polymerization method. The structures of the copolymers were characterized by Fourier transform infrared, UVVis, 1H NMR, 13C NMR, gel permeation chromatography, thermogravimetric analyses, and scanning electron microscopy (SEM). The results presented show that C60 and vinylpyrrolidone (VP) can be copolymerized under different conditions. With a constant benzoyl peroxide amount, C60 contents in the copolymers increase with increasing initial C60:VP reactant ratio. The assembly behavior of water-soluble C60N-vinylpyrrolidone copolymers was investigated by SEM. The results show that the copolymers create morphology that is sphere-like. Fullerene-containing micro-/nano-sized copolymer fibers were prepared, for the first time, by electrospinning. The cytotoxicity to cancer cell lines of the copolymers was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and confocal laser scanning microscope. The results show that copolymers exhibit better cytotoxicity against HeLa cells and mouse osteogenic sarcoma cells (cytotoxicity of copolymers is better than that of fullerene complex). The mechanism of fullereneVP copolymerization was investigated for the first time. (c) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012