title: Tailorable cell culture platforms from enzymatically cross-linked multifunctional poly(ethylene glycol)-based hydrogels.
abstract: As stem-cell-based therapies rapidly advance toward clinical applications, there is a need for cheap, easily manufactured, injectable gels that can be tailored to carry stem cells and impart function to such cells. Herein we describe a process for making hydrogels composed of hydroxyphenyl propionic acid (HPA) conjugated, branched poly(ethylene glycol) (PEG) via an enzyme mediated, oxidative cross-linking method. Functionalization of the branched PEG with HPA at varying degrees of substitution was confirmed via attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and (1)H NMR. The versatility of this hydrogel system was exemplified through variations in the degree of HPA substitution, polymer concentration, and the concentration of cross-linking reagents (horseradish peroxidase and H(2)O(2)), which resulted in a range of mechanical properties and gelation kinetics for these gels. Cross-linking of the PEG-HPA conjugate with a recombinantly produced Fibronectin fragment (Type III domains 7-10) encouraged attachment and spreading of human mesenchymal stem cells (hMSCs) when assessed in both two-dimensional and three-dimensional formats. Interestingly, when encapsulated in both nonfunctionalized and functionalized cross-linked PEG-HPA gels, MSCs showed good viability over all time periods assessed. With tunable gelation kinetics and mechanical properties, these hydrogels provide a flexible in vitro cell culture platform that will likely have significant utility in tissue engineering as an injectable delivery platform for cells to sites of tissue damage.
authors.affiliation: Tissue Engineering and Microfluidics Laboratory, The Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, QLD, Australia.
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Menzies
authors.forename: Andrew
authors.initials: A
authors.lastname: Cameron
authors.forename: Trent
authors.initials: T
authors.lastname: Munro
authors.forename: Ernst
authors.initials: E
authors.lastname: Wolvetang
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Grøndahl
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Cooper-White
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010666:Phenylpropionates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D020100:Hydrogels; D010666:Phenylpropionates; D011108:Polymers; D011092:Polyethylene Glycols