title: Effect of nanoscale topography on fibronectin adsorption, focal adhesion size and matrix organisation.
abstract: Phase separation of PLLA/PS (50/50, w/w) solutions during a spin-casting process gives rise to well-defined nanotopographies of 14, 29 and 45 nm deep pits depending on the concentration of the solution. Their influence on the biological activity of fibronectin (FN) was investigated. FN adsorption was quantified by radiolabelling the protein. The amount of adsorbed FN was higher on the 14 nm deep pit nanotopography than on the other two surfaces. FN distribution between valleys and peaks was investigated by AFM combined with image analysis. FN tends to adsorb preferentially on the valleys of the nanotopography only for the 14 nm system and when adsorbed from solutions of concentration lower than 10 microg/ml. Higher concentration of the FN solution leads to evenly distribution of the protein throughout the surface; moreover, there is no difference in the distribution of the protein between valleys and peaks for the other two systems (29 and 45 nm) irrespective of the concentration of the FN solution. The biological activity of the adsorbed protein layer was assessed by investigating MC3T3 osteoblast-like cells adhesion, FN reorganisation and late matrix formation on the different substrates. Even if initial cell adhesion is excellent for every substrate, the size of the focal adhesion plaques increases as the size of the pits in the nanotopography does. This is correlated to FN reorganisation, which only takes places on the 29 and 45 nm deep pits surfaces, where enhanced late matrix production was also found.
authors.affiliation: Center for Biomaterials and Tissue Engineering, Universidad Politécnica de Valencia, 46022 Valencia, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: González-García
authors.forename: Susana R
authors.initials: SR
authors.lastname: Sousa
authors.forename: David
authors.initials: D
authors.lastname: Moratal
authors.forename: Patricia
authors.initials: P
authors.lastname: Rico
authors.forename: Manuel
authors.initials: M
authors.lastname: Salmerón-Sánchez
mesh_terms: D016475:3T3 Cells; D000327:Adsorption; D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D005353:Fibronectins / Q000737:chemistry*; D022001:Focal Adhesions / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D051379:Mice; D018625:Microscopy, Atomic Force / Q000379:methods; D036103:Nanotechnology / Q000379:methods; D010006:Osteoblasts / Q000166:cytology; D011506:Proteins / Q000737:chemistry; D013499:Surface Properties
chemical_list: D005353:Fibronectins; D011506:Proteins