Photodynamic Activity of Fullerene Derivatives Solubilized in Water by Natural-Product-Based Solubilizing Agents.

Water-soluble fullerenes prepared by using solubilizing agents based on natural products are promising photosensitizers for photodynamic therapy. Cyclodextrin, β-1,3-glucan, lysozyme, and liposomes can stably solubilize not only C60 and C70 , but also some C60 derivatives in water. To improve the solubilities of fullerenes, specific methods have been developed for each solubilizing agent. Water-soluble C60 and C70 exhibit photoinduced cytotoxicity under near-ultraviolet irradiation, but not at wavelengths over 600 nm, which are the appropriate wavelengths for photodynamic therapy. However, dyad complexes of solubilized C60 derivatives combined with light-harvesting antenna molecules improve the photoinduced cytotoxicities at wavelengths over 600 nm. Furthermore, controlling the fullerene and antenna molecule positions within the solubilizing agents affects the performance of the photosensitizer.