title: Synthesis and characterization of novel thiol-reactive poly(ethylene glycol) cross-linkers for extracellular-matrix-mimetic biomaterials.
abstract: Synthetic extracellular matrix hydrogels can be used for three-dimensional cell culture, wound repair, and tissue engineering. Using the bifunctional electrophile poly(ethylene glycol) diacrylate (PEGDA), thiol-modified glycosaminoglycans and polypeptides can be cross-linked into biocompatible materials in the presence of cells or tissues. However, the rate of in situ cross-linking with PEGDA under physiological conditions may occur too slowly for clinical applications requiring a fast-curing preparation. To explore a wider range of cross-linking time courses, five homo-bifunctional PEG derivatives were synthesized and examined as cross-linking agents for thiol-modified derivatives of hyaluronan (HA). Thiol reaction rate constants were measured over a pH range of 7.4 to 8.6. The order of reactivity for the functional groups used was determined to be maleimide > iodoacetate > bromoacetate > iodoacetamide > acrylate > bromoacetamide, with rates increasing exponentially with increasing pH. The range of gelation times at physiological pH varied from less than 1 min to over 2 h. Addition of the cross-linkers to cell culture medium showed minimal cytotoxicity toward primary human dermal fibroblasts at concentrations anticipated during in situ cross-linking. Moreover, hydrogels prepared from thiol-modified gelatin and thiol-modified HA were biocompatible and supported attachment and proliferation of fibroblasts and hepatocytes.
authors: Department of Bioengineering, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108-1257, USA.
authors: Janssen L
authors: JL
authors: Vanderhooft
authors: Brenda K
authors: BK
authors: Mann
authors: Glenn D
authors: GD
authors: Prestwich
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002460:Cell Line; D005109:Extracellular Matrix / Q000737:chemistry*; D006801:Humans; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000138:chemical synthesis*
chemical_list: D001672:Biocompatible Materials; D011092:Polyethylene Glycols