title: Biologically engineered protein-graft-poly(ethylene glycol) hydrogels: a cell adhesive and plasmin-degradable biosynthetic material for tissue repair.
abstract: To address the need for bioactive materials toward clinical applications in wound healing and tissue regeneration, an artificial protein was created by recombinant DNA methods and modified by grafting of poly(ethylene glycol) diacrylate. Subsequent photopolymerization of the acrylate-containing precursors yielded protein-graft-poly(ethylene glycol) hydrogels. The artificial protein contained repeating amino acid sequences based on fibrinogen and anti-thrombin III, comprising an RGD integrin-binding motif, two plasmin degradation sites, and a heparin-binding site. Two-dimensional adhesion studies showed that the artificial protein had specific integrin-binding capability based on the RGD motif contained in its fibrinogen-based sequence. Furthermore, heparin bound strongly to the protein's anti-thrombin III-based region. Protein-graft-poly(ethylene glycol) hydrogels were plasmin degradable, had Young's moduli up to 3.5 kPa, and supported three-dimensional outgrowth of human fibroblasts. Cell attachment in three dimensions resulted from specific cell-surface integrin binding to the material's RGD sequence. Hydrogel penetration by cells involved serine-protease mediated matrix degradation in temporal and spatial synchrony with cellular outgrowth. Protein-graft-poly(ethylene glycol) hydrogels represent a new and versatile class of biomimetic hybrid materials that hold clinical promise in serving as implants to promote wound healing and tissue regeneration.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.
authors.forename: Sven
authors.initials: S
authors.lastname: Halstenberg
authors.forename: Alyssa
authors.initials: A
authors.lastname: Panitch
authors.forename: Simone
authors.initials: S
authors.lastname: Rizzi
authors.forename: Heike
authors.initials: H
authors.lastname: Hall
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hubbell
mesh_terms: D020341:Absorbable Implants; D000595:Amino Acid Sequence; D000990:Antithrombin III / Q000235:genetics; D002448:Cell Adhesion; D005340:Fibrinogen / Q000235:genetics; D005341:Fibrinolysin / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D020100:Hydrogels / Q000138:chemical synthesis*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000235:genetics; D010446:Peptide Fragments / Q000235:genetics; D011092:Polyethylene Glycols / Q000737:chemistry; D015202:Protein Engineering / Q000379:methods; D011994:Recombinant Proteins / Q000138:chemical synthesis*; D014014:Tissue Adhesives / Q000138:chemical synthesis*
chemical_list: D020100:Hydrogels; D009842:Oligopeptides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014014:Tissue Adhesives; D011092:Polyethylene Glycols; C047981:arginyl-glycyl-aspartic acid; D000990:Antithrombin III; D005340:Fibrinogen; D005341:Fibrinolysin