title: Dynamic heterodimer-functionalized surfaces for endothelial cell adhesion.
abstract: The functionalization of hydrogels for receptor-mediated cell adhesion is one approach for targeted cell and tissue engineering applications. In this study, polyacrylamide gel surfaces were functionalized with specific cell adhesion ligands via the self-assembly of a peptide-based heterodimer. The system was comprised of a cysteine-terminated monomer, A (MW approximately 5400), grafted to the polyacrylamide gels and a complementary ligand presenting monomer, B(X) (MW approximately 5800) that was designed to heterodimerize with A. Two ligand presenting monomers were synthesized: one presenting the RGDS ligand, B(D), for receptor-mediated cell adhesion, and the other, a control monomer presenting the nonadhesive RGES ligand, B(E). Assembly of the peptide pair A-B(X) by association of the monomers into a coiled coil was verified by circular dichroism in solution. Binding studies were conducted to determine the dissociation constant of the pair A-B(X), which was found to be K(D) approximately 10(-8) m. Polyacrylamide gels functionalized with A-B(X) heterodimers were evaluated for cell adhesion using bovine aortic endothelial cells (BAECs). Endothelial cells cultured on the A-B(D) functionalized surfaces demonstrated typical cell morphologies and expected spreading behavior as a function of the density of RGDS ligand, calculated as the amount of B(D) associated with grafted A on the surface of the gels. In contrast, A-B(E) linked surfaces supported no cell adhesion. The adhesion of the substrate was dynamically altered through the reassembly of A-B(X) dimers as B(D) molecules in the solution replaced B(E) molecules at the substrate. The molecular constructs described here demonstrate the potential to design a broad family of switchable peptides that impart the dynamic control of biofunctionality at an interface, which would be useful for precise manipulation of cell physiology.
authors.affiliation: Department of Bioengineering, University of Pennsylvania, 3320 Smith Walk, 120 Hayden Hall, Philadelphia, PA 19104, USA.
authors.forename: P Jeanene
authors.initials: PJ
authors.lastname: Willcox
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Reinhart-King
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lahr
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hammer
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology*; D019281:Dimerization; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D008422:Materials Testing; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D011485:Protein Binding; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D020099:Coated Materials, Biocompatible; D009842:Oligopeptides; C046617:arginyl-glycyl-aspartyl-serine