title: Different Organization of Type I Collagen Immobilized on Silanized and Nonsilanized Titanium Surfaces Affects Fibroblast Adhesion and Fibronectin Secretion.
abstract: Silanization has emerged in recent years as a way to obtain a stronger and more stable attachment of biomolecules to metallic substrates. However, its impact on protein conformation, a key aspect that influences cell response, has hardly been studied. In this work, we analyzed by atomic force microscopy (AFM) the distribution and conformation of type I collagen on plasma-treated surfaces before and after silanization. Subsequently, we investigated the effect of the different collagen conformations on fibroblasts adhesion and fibronectin secretion by immunofluorescence analyses. Two different organosilanes were used on plasma-treated titanium surfaces, either 3-chloropropyl-triethoxy-silane (CPTES) or 3-glycidyloxypropyl-triethoxy-silane (GPTES). The properties and amount of the adsorbed collagen were assessed by contact angle, X-ray photoelectron spectroscopy, optical waveguide lightmode spectroscopy, and AFM. AFM studies revealed different conformations of type I collagen depending on the silane employed. Collagen was organized in fibrillar networks over very hydrophilic (plasma treated titanium) or hydrophobic (silanized with CPTES) surfaces, the latter forming little globules with a beads-on-a-string appearance, whereas over surfaces presenting an intermediate hydrophobic character (silanized with GPTES), collagen was organized into clusters with a size increasing at higher protein concentration in solution. Cell response was strongly affected by collagen conformation, especially at low collagen density. The samples exhibiting collagen organized in globular clusters (GPTES-functionalized samples) favored a faster and better fibroblast adhesion as well as better cell spreading, focal adhesions formation, and more pronounced fibronectin fibrillogenesis. In contrast, when a certain protein concentration was reached at the material surface, the effect of collagen conformation was masked, and similar fibroblast response was observed in all samples.
authors: Biomaterials, Biomechanics, and Tissue Engineering Group, Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya. BarcelonaTech (UPC) , Av. Diagonal 647, 08028 Barcelona, Spain.
authors: Nathalia
authors: N
authors: Marín-Pareja
authors: Division of Biomedical Engineering, School of Engineering, University of Glasgow , Glasgow G12 8LT, U.K.
authors: Marco
authors: M
authors: Cantini
authors: Division of Biomedical Engineering, School of Engineering, University of Glasgow , Glasgow G12 8LT, U.K.
authors: Cristina
authors: C
authors: González-García
authors: Biomaterials, Biomechanics, and Tissue Engineering Group, Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya. BarcelonaTech (UPC) , Av. Diagonal 647, 08028 Barcelona, Spain.
authors: Emiliano
authors: E
authors: Salvagni
authors: Division of Biomedical Engineering, School of Engineering, University of Glasgow , Glasgow G12 8LT, U.K.
authors: Manuel
authors: M
authors: Salmerón-Sánchez
authors: Biomaterials, Biomechanics, and Tissue Engineering Group, Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya. BarcelonaTech (UPC) , Av. Diagonal 647, 08028 Barcelona, Spain.
authors: Maria-Pau
authors: MP
authors: Ginebra
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D055767:Immobilized Proteins / Q000494:pharmacology*; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000494:pharmacology*; D016596:Vinculin / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D005353:Fibronectins; D055767:Immobilized Proteins; D012821:Silanes; D016596:Vinculin; D014025:Titanium
keywords: adhesion; atomic force microscopy; collagen conformation; dental implant; fibroblast; fibronectin; silanization; titanium