title: Characterization of protein release from poly(ethylene glycol) hydrogels with crosslink density gradients.
abstract: Transplantation of cells within poly(ethylene glycol) (PEG) hydrogel scaffolds as effective immunoisolation barriers is becoming increasingly important strategy for tissue engineering and regenerative medicine. In these applications, crosslink density of these membranes has significant effect on the control of diffusion of many biomolecules such as nutrients, cellular wastes, and hormones. When these networks are designed with crosslink density gradients, alterations in network structure may have an effect on biomolecule diffusivity. The goal of this work was to synthesize PEG hydrogels via surface initiated photopolymerization for use in applications involving physiological protein delivery and cell encapsulation. For this purpose, PEG hydrogels of differing crosslink density gradients were formed via surface initiated photopolymerization, and the diffusion of model proteins with various molecular weights were observed through these PEG hydrogel scaffolds with defined properties. Diffusion coefficients were on the order of 10(-7) -10(-8) cm(2) /s and protein diffusion time scales varied from 5 min to 30 h. The results confirm that synthetic PEG hydrogels with crosslink density gradients are promising for controlled release of bioactive molecules and for covalent incorporation of ligands to support cell viability.
authors.affiliation: Department of Chemical and Biological Engineering, College of Engineering, Koc University, 34450, Sariyer, Istanbul, Turkey.
authors.forename: Tuğba
authors.initials: T
authors.lastname: Bal
authors.forename: Burcu
authors.initials: B
authors.lastname: Kepsutlu
authors.forename: Seda
authors.initials: S
authors.lastname: Kizilel
mesh_terms: D000818:Animals; D018914:Cells, Immobilized / Q000737:chemistry / Q000166:cytology / Q000637:transplantation; D052216:Glucagon-Like Peptide 1 / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D051379:Mice; D041681:NIH 3T3 Cells; D011092:Polyethylene Glycols / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D020100:Hydrogels; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D052216:Glucagon-Like Peptide 1
keywords: BSA, swelling, protein release; PEG hydrogel; cell viability; glucagon-like peptide (GLP-1); surface initiated photopolymerization