Cyclodextrin Complexed [60]Fullerene Derivatives with High Levels of Photodynamic Activity by Long Wavelength Excitation

We have evaluated the photodynamic activities of C-60 derivative center dot gamma-cyclodextrin (gamma-CDx) complexes and demonstrated that they were significantly higher than those of the pristine C-60 and C-70 center dot gamma-CDx complexes under photoirradiation at long wavelengths (610-720 nm), which represent the optimal wavelengths for photodynamic therapy (PDT). In particular, the cationic C-60 derivative center dot gamma-CDx complex had the highest photodynamic ability because the complex possessed the ability to generate high levels of O-1(2) and provided a higher level of intracellular uptake. The photodynamic activity of this complex was greater than that of photofrin, which is the most widely used of the known clinical photosensitizers. These findings therefore provide a significant level of information toward the optimization of molecular design strategies for the synthesis of fullerene derivatives for PDT.