Synthesis and characterization of injectable supramolecular structured hydrogels prepared by free radical polymerization of PLA-b-PEG-b-PLA macromers and α-cyclodextrins

Poly(L-lactide)-poly(ethylene glycol)-poly(L-lactide) triblock copolymer (PLA-PEG-PLA) was synthesized by the ring-opening polymerization of L-lactide with poly(ethylene glycol) (PEG6000) as the initiator and Sn(Oct)₂ as the catalyst in toluene. This copolymer was further reacted with methacrylic anhydride to give a soluble macromer terminated with methacryloyl groups. Two kinds of supramolecular structured hydro-gels were obtained through mixing the macromer with α-cyclodextrins and then initiating by using ammonium persulphate with ascorbic acid or ferrous sulfate. The macromer and hydrogels were characterized by ¹H NMR, FTIR, TGA and XRD etc.. Based on rheological test, the two kinds of the resultant hydrogels are injectable with appropriate pot-life.