Anionic and neutral fullerene derivatives were dissolved in water by 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 ca. 0.30 mM and the average particle sizes were ca. 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) when compared with that of 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 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.

This work was supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (B) (Grant No. JP16H04133) and Grant-in-Aid for Challenging Exploratory Research (Grant No. JP16K13982).