Influence of Amide versus Ester Linkages on the Properties of Eight-Armed PEG-PLA Star Block Copolymer Hydrogels

• DOI: 10.1021/bm901080d
• Publication Date: 2009-11-25T18:48:03Z
• Authors: Sytze J. Buwalda; Pieter J. Dijkstra; Lucia Calucci; Claudia Forte; Jan Feijen
• Keywords: Amide; Lactide

Water-soluble eight-armed poly(ethylene glycol)-poly(l-lactide) star block copolymers linked by an amide or ester group between the PEG core and PLA blocks (PEG-(NHCO)-(PLA)(8) PEG-(OCO)-(PLA)(8)) were synthesized stannous octoate catalyzed ring-opening polymerization of l-lactide using amine- hydroxyl-terminated PEG. At concentrations above critical gel concentration, thermosensitive hydrogels obtained, showing a reversible single gel-to-sol transition. similar composition PEG-(NHCO)-(PLA)(8) formed at significantly lower polymer had higher storage moduli. Whereas hydrolytic degradation/dissolution PEG-(OCO)-(PLA)(8) takes place preferential hydrolysis bond block, degrade through bonds in main chain. Because their relatively good mechanical properties slow degradation vitro, are interesting materials for biomedical applications such as controlled drug delivery systems matrices tissue engineering.