An injectable thiol-acrylate poly(ethylene glycol) hydrogel for sustained release of methylprednisolone sodium succinate

Clinically available injectable hydrogels face technical challenges associated with swelling after injection and toxicity from unreacted constituents that impede their performance as surgical biomaterials To overcome these challenges we developed a system where chemical gelation was controlled by a conjugate Michael addition between thiol and acrylate in aqueous media with 97% monomer conversion and 6 wt % sol fraction The hydrogel exhibited syneresis on equilibration reducing to 59 7% of its initial volume It had mechanical properties similar to soft human tissue with an elastic modulus of 189 8 kPa Furthermore a mesh size of 69 nm resulted in sustained release of methylprednisolone sodium succinate with a loading efficiency of 2 mg/mL Functionalization with 50 mu g/mL of an oligolysine peptide resulted in attachment of freshly Isolated munne mesenchymal stem cells The rational design of the physical chemical and biological properties of the hydrogel makes It a potentially promising candidate for injectable applications (C) 2010 Elsevier Ltd All rights reserved