Structural Effect and Mechanism of C70-Carboxyfullerenes as Efficient Sensitizers against Cancer Cells

Carboxyfullerenes with different adduct numbers and cage sizes are tested as photosensitizers for photodynamic therapy (PDT). The photodynamic efficiency of these carboxyfullerenes depends mainly on the cage size, C60 versus C70, and to a lesser extent on the adduct numbers. In particular, malonic acid modified C70 fullerenes are more efficient than their C60 counterparts as photosensitizers, and the mechanism of cell death induced by C70-carboxyfullerene under light irradiation is investigated in detail. The results indicate that cell death occurs via necrosis accompanied by membrane blebbing, which is a unique phenomenon for photosensitizer-induced cell death. Since C70-carboxyfullerene displays an efficient PDT property and negligible dark cytotoxicity, it is promising for use in PDT applications, especially in vascular capillary diseases usually occurring under the surface.