title: Polyelectrolyte multilayers with a tunable Young's modulus: influence of film stiffness on cell adhesion.
abstract: Mechanical properties of model and natural gels have recently been demonstrated to play an important role in various cellular processes such as adhesion, proliferation, and differentiation, besides events triggered by chemical ligands. Understanding the biomaterial/cell interface is particularly important in many tissue engineering applications and in implant surgery. One of the final goals would be to control cellular processes precisely at the biomaterial surface and to guide tissue regeneration. In this work, we investigate the substrate mechanical effect on cell adhesion for thin polyelectrolyte multilayer (PEM) films, which can be easily deposited on any type of material. The films were cross linked by means of a water-soluble carbodiimide (EDC), and the film elastic modulus was determined using the AFM nanoindentation technique with a colloidal probe. The Young's modulus could be varied over 2 orders of magnitude (from 3 to 400 kPa) for wet poly(L-lysine)/hyaluronan (PLL/HA) films by changing the EDC concentration. The chemical changes upon cross linking were characterized by means of Fourier transform infrared spectroscopy (FTIR). We demonstrated that the adhesion and spreading of human chondrosarcoma cells directly depend on the Young's modulus. These data indicate that, besides the chemical properties of the polyelectrolytes, the substrate mechanics of PEM films is an important parameter influencing cell adhesion and that PEM offer a new way to prepare thin films of tunable mechanical properties with large potential biomedical applications including drug release.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 595, Faculté de Chirurgie Dentaire, Université Louis Pasteur, 11 rue Humann, 67085 Strasbourg Cedex, France.
authors.forename: Aurore
authors.initials: A
authors.lastname: Schneider
authors.forename: Grégory
authors.initials: G
authors.lastname: Francius
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Obeid
authors.forename: Pascale
authors.initials: P
authors.lastname: Schwinté
authors.forename: Joseph
authors.initials: J
authors.lastname: Hemmerlé
authors.forename: Benoît
authors.initials: B
authors.lastname: Frisch
authors.forename: Pierre
authors.initials: P
authors.lastname: Schaaf
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Voegel
authors.forename: Bernard
authors.initials: B
authors.lastname: Senger
authors.forename: Catherine
authors.initials: C
authors.lastname: Picart
mesh_terms: D002234:Carbodiimides / Q000737:chemistry; D002448:Cell Adhesion; D002813:Chondrosarcoma / Q000473:pathology; D004573:Electrolytes / Q000737:chemistry*; D006801:Humans; D017550:Spectroscopy, Fourier Transform Infrared; D014407:Tumor Cells, Cultured
chemical_list: D002234:Carbodiimides; D004573:Electrolytes