title: Early adhesion of human mesenchymal stem cells on TiO(2)  surfaces studied by single-cell force spectroscopy measurements.
abstract: Understanding the interactions involved in the adhesion of living cells on surfaces is essential in the field of tissue engineering and biomaterials. In this study, we investigate the early adhesion of living human mesenchymal stem cells (hMSCs) on flat titanium dioxide (TiO(2) ) and on nanoporous crystallized TiO(2) surfaces with the use of atomic force microscopy-based single-cell force spectroscopy measurements. The choice of the substrate surfaces was motivated by the fact that implants widely used in orthopaedic and dental surgery are made in Ti and its alloys. Nanoporous TiO(2) surfaces were produced by anodization of Ti surfaces. In a typical force spectroscopy experiment, one living hMSC, immobilized onto a fibronectine-functionalized tipless lever is brought in contact with the surface of interest for 30 s before being detached while recording force-distance curves. Adhesion of hMSCs on nanoporous TiO(2) substrates having inner pore diameter of 45 nm was lower by approximately 25% than on TiO(2) flat surfaces. Force-distance curves exhibited also force steps that can be related to the pulling of membrane tethers from the cell membrane. The mean force step was equal to 35 pN for a given speed independently of the substrate surface probed. The number of tethers observed was substrate dependent. Our results suggest that the strength of the initial adhesion between hMSCs and flat or nanoporous TiO(2) surfaces is driven by the adsorption of proteins deposited from serum in the culture media.
authors.affiliation: Université de Nantes/CNRS, UMR 6502, Institut des Matériaux Jean Rouxel, 2 rue de la Houssinière, BP 32229, 44322 Nantes cedex 3, France. Patricia.Bertoncini@cnrs-imn.fr
authors.forename: P
authors.initials: P
authors.lastname: Bertoncini
authors.forename: S
authors.initials: S
authors.lastname: Le Chevalier
authors.forename: S
authors.initials: S
authors.lastname: Lavenus
authors.forename: P
authors.initials: P
authors.lastname: Layrolle
authors.forename: G
authors.initials: G
authors.lastname: Louarn
mesh_terms: D000497:Alloys; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure*; D018625:Microscopy, Atomic Force; D043942:Nanotubes; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; C009495:titanium dioxide; D014025:Titanium