Water Solubilization of Fullerene Derivatives by β-(1,3-1,6)-d-Glucan and Their Photodynamic Activities toward Macrophages.

Anionic and neutral fullerene derivatives were dissolved in water by using β-(1,3-1,6)-d-glucan (β-1,3-glucan) as a solubilizing agent. In the water-solubilized complexes, the concentrations of fullerene derivatives were ≈0.30 mm and the average particle sizes were ≈90 nm. The β-1,3-glucan-complexed fullerene derivative with a carboxylic acid was found to have higher photodynamic activity toward macrophages under visible-light irradiation (λ>610 nm) than other β-1,3-glucan-complexed fullerene derivatives. This result suggests that carboxylic acid moieties in the complex enhance the binding affinity with β-1,3-glucan receptors on the surface of macrophages when the β-1,3-glucan is recognized. In contrast, all β-1,3-glucan-complexed fullerene derivatives showed no photodynamic activity toward HeLa cells under the same conditions.