Formation of Water-Soluble Complexes from Fullerene with Biocompatible Block Copolymers Bearing Pendant Glucose and Phosphorylcholine.

Double-hydrophilic diblock copolymers, PMPC 100 - block -PGEMA n (M 100 G n ), were synthesized via reversible addition-fragmentation chain transfer radical polymerization using glycosyloxyethyl methacrylate and 2-(methacryloyloxy)ethyl phosphorylcholine. The degree of polymerization (DP) of the poly(2-(methacryloyloxy) ethylphosphorylcholine) (PMPC) block was 100, whereas the DPs ( n ) of the poly(glycosyloxyethyl methacrylate) PGEMA block were 18, 48, and 90. Water-soluble complexes of C 70 /M 100 G n and fullerene (C 70 ) were prepared by grinding M 100 G n and C 70 powders in a mortar and adding phosphate-buffered saline (PBS) solution. PMPC can form a water-soluble complex with hydrophobic C 70 using the same method. Therefore, the C 70 /M 100 G n complexes have a core-shell micelle-like particle structure possessing a C 70 /PMPC core and PGEMA shells. The maximum amounts of solubilization of C 70 in PBS solutions using 2 g/L each of M 100 G 18 , M 100 G 48 , and M 100 G 90 were 0.518, 0.358, and 0.257 g/L, respectively. The hydrodynamic radius ( R h ) of C 70 /M 100 G n in PBS solutions was 55-75 nm. Spherical aggregates with a similar size to the R h were observed by transmission electron microscopy. When the C 70 /M 100 G n PBS solutions were irradiated with visible light, singlet oxygen was generated from C 70 in the core. It is expected that the C 70 /M 100 G n complexes can be applied to photosensitizers for photodynamic therapy treatments.