C60-containing nanostructured polymeric materials with potential biomedical applications

Star-shaped polymers with a fullerene (C60) core and an unexpanded structure were successfully prepared by reaction of C60 with amino end-capped polyesters HxC60(NHPCLn)x and polyethers HxC60(NHPEGn)x, respectively. Upon irradiation of these C60-derivatives, a large amount of singlet oxygen was released. Compared to previously synthesized star-shaped azafulleroids with an expanded structure, the photosensitivity of HxC60(NHPCLn)x is higher as assessed by a higher production of singlet oxygen. The cytotoxicity of the photoactive water-soluble HxC60(NHPEGn)x derivatives was tested against THP-1 cells and expressed in terms of cell viability. Moreover, they were processed as micro-/nanosized fibers by electrospinning, which however required the addition of poly(ε-caprolactone) (PCL). The diameter distribution of the fibers was trimodal, where the fraction with the 270 nm average diameter was the major population. Because of their photoactivity, the herein reported star-shaped C60-derivatives are promising candidates for photodynamic cancer therapy and treatment of multidrug resistant pathogens.