title: Effects of the poly(ethylene glycol) hydrogel crosslinking mechanism on protein release.
abstract: Poly(ethylene glycol) (PEG) hydrogels are widely used to deliver therapeutic biomolecules, due to high hydrophilicity, tunable physicochemical properties, and anti-fouling properties. Although different hydrogel crosslinking mechanisms are known to result in distinct network structures, it is still unknown how these various mechanisms influence biomolecule release. Here we compared the effects of chain-growth and step-growth polymerization for hydrogel crosslinking on the efficiency of protein release and diffusivity. For chain-growth-polymerized PEG hydrogels, while decreasing PEG concentration increased both the protein release efficiency and diffusivity, it was unexpected to find out that increasing PEG molecular weight did not significantly change either parameter. In contrast, for step-growth-polymerized PEG hydrogels, both decreasing PEG concentration and increasing PEG molecular weight resulted in an increase in the protein release efficiency and diffusivity. For step-growth-polymerized hydrogels, the protein release efficiency and diffusivity were further decreased by increasing crosslink functionality (4-arm to 8-arm) of the chosen monomer. Altogether, our results demonstrate that the crosslinking mechanism has a differential effect on controlling protein release, and this study provides valuable information for the rational design of hydrogels for sophisticated drug delivery.
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California, USA.
authors.forename: Soah
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA.
authors.forename: Xinming
authors.initials: X
authors.lastname: Tong
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA and Department of Bioengineering, Stanford University, Stanford, California 94305, USA. fanyang@stanford.edu.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
mesh_terms: D016503:Drug Delivery Systems / Q000379:methods*; D065546:Drug Liberation / Q000187:drug effects* / Q000502:physiology; D020100:Hydrogels / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization
chemical_list: D020100:Hydrogels; D011092:Polyethylene Glycols