Core-polymerized reactive micelles from heterotelechelic amphiphilic blockcopolymers

Amphiphilic poly(ethylene glycol)-b-polylactide (PEG/PLA) copolymers with a n aldehyde group at one end and a methacryloyl group at the other chain end were synthesized by anionic polymerization. The efficiencies of the functi onalization at both ends were almost quantitative. The amphiphilic block co polymers formed micelles in aqueous media. Acetal groups on the micelle! su rface were quantitatively converted to aldehyde groups by an acid treatment . The end methacryloyl group located in the core of the micelle was polymer ized effectively to form core-shell-type nanoparticles having reactive alde hyde groups on the surface. The, size of the reactive nanoparticle was 20-3 0 nm which was constant with temperatures up to 60 DC. The stability of the micelle was also confirmed by a sodium dodecyl sulfate (SDS) treatment. Wh en SDS was added to the nanosphere solution to 20 mg/mL, the particle was n ot collapsed. The particle was stable enough even in organic solvents. This functionalized micelle having high stability is not only expected to have wide utilities in biomedical applications (including drug delivery, diagnos is, and surface modification through the coupling of bioactive substances) but also to be of great interest as a novel supramolecular architecture.