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

Christopher D. Pritchard, Timothy M. O'Shea, Daniel J. Siegwart, Eliezer Calo, Daniel G. Anderson, Francis M. Reynolds, John A. Thomas, Jonathan R. Slotkin, Eric J. Woodard, Robert Langer

Research output: Contribution to journalArticle

96 Scopus citations


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 6.9 nm resulted in sustained release of methylprednisolone sodium succinate with a loading efficiency of 2 mg/mL. Functionalization with 50 μg/mL of an oligolysine peptide resulted in attachment of freshly isolated murine 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.

Original languageEnglish (US)
Pages (from-to)587-597
Number of pages11
Issue number2
Publication statusPublished - Jan 2011



  • Cell adhesion
  • Controlled drug release
  • Hydrogel
  • Peptide
  • Polyethylene oxide
  • Spinal surgery

ASJC Scopus subject areas

  • Biomaterials
  • Bioengineering
  • Ceramics and Composites
  • Mechanics of Materials
  • Biophysics

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