Proteolytically activated anti-bacterial hydrogel microspheres
journal contributionposted on 2014-01-02, 00:00 authored by Jason S. Buhrman, Laura C. Cook, Jamie E. Rayahin, Michael J. Federle, Richard A. Gemeinhart
Hydrogels are finding increased clinical utility as advances continue to exploit their favorable material properties. Hydrogels can be adapted for many applications, including surface coatings and drug delivery. Anti-infectious surfaces and delivery systems that actively destroy invading organisms are alternative ways to exploit the favorable material properties offered by hydrogels. Sterilization techniques are commonly employed to ensure the materials are non-infectious upon placement, but sterilization is not absolute and infections are still expected. Natural, anti-bacterial proteins have been discovered which have the potential to act as anti-infectious agents; however, the proteins are toxic and need localized release to have therapeutic efficacy without toxicity. In these studies, we explore the use of the glutathione s-transferase (GST) to anchor the bactericidal peptide, melittin, to the surface of poly(ethylene glycol) diacrylate (PEGDA) hydrogel microspheres. We show that therapeutic levels of protein can be anchored to the surface of the microspheres using the GST anchor. We compared the therapeutic efficacy of recombinant melittin released from PEGDA microspheres to melittin. We found that, when released by an activating enzyme, thrombin, recombinant melittin efficiently inhibits growth of the pathogenic bacterium Streptococcus pyogenes as effectively as melittin created by solid phase peptide synthesis. We conclude that a GST protein anchor can be used to immobilize functional protein to PEGDA microspheres and the protein will remain immobilized under physiological conditions until the protein is enzymatically released.
This research has been funded, in part, by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award supported by the NCRR (UL1 TR000050, RAG), and the National Institute for Neurologic Disorders and Stroke (NS055095, RAG) and the National Institute of Allergy and Infectious Diseases (AI091779, MJF).
Publisher StatementNOTICE: This is the author’s version of a work that was accepted for publication in Journal of Controlled Release. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for Journal of Controlled Release. A definitive version was subsequently published in Journal of Controlled Release, Vol 171, Issue 3, 2013 DOI: 10.1016/j.jconrel.2013.06.023