Preparation of a thermosensitive and biodegradable microgel via polymerization of macromonomers based on diacrylated Pluronic/oligoester copolymers

A novel biodegradable and thermosensitive hydrogel microparticle was prepared via suspension polymerization of a kind of block copolymer macromonomers. According to the molecular design, the macromonomer is composed of a thermosensitive triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPOPEO) and two oligomers of biodegradable polyester such as oligo(lactic acid) or oligo(epsilon-caprolactone), and end-capped with acryloyl groups. Microgels were obtained by inverse suspension polymerization of the macromonomer aqueous droplets initiated by a redox initiator. Thermo sensitivity and in vitro biodegradation of the resultant microgels were confirmed. The gel microparticles in an aqueous solution were swollen at low temperature and shrunken at high temperature (human body temperature). Degradation rate could be adjusted by controlling the composition and the degree of polymerization of oligoester. Thus, the microgels exhibit combinatory and tunable properties. (c) 2005 Elsevier Ltd. All rights reserved.