Novel Thermoreversible Gelation of Biodegradable PLGA-block-PEO-block-PLGA Triblock Copolymers in Aqueous Solution

Abstract

The BAB-type triblock copolymers composed of a central poly(ethylene oxide) (PEO, M̄nPEO = 1 000) block and two poly[(D,L-lactic acid)-co-(glycolic acid)] end blocks with molecular weights between 900 and 1 600 exhibited an interesting phase transition behavior. The copolymer aqueous solution can form micelles with PLGA loops in the core and a PEO shell and groups of micelles because of bridging between micelles caused by the PLGA blocks with raising temperature. A possible micellar gelation mechanism was suggested.