Creation of nanostructures to study the topographical dependency of protein adsorption

Abstract

Nanostructures of sizes comparable to protein dimensions are created on Si and Ti surfaces by local anodic oxidation (LAO) using the atomic force microscope (AFM). The characterization of the surface by X-ray photoelectron spectroscopy (XPS) reveals that this method assures a modification of the topography of the surface without a change of its chemical composition. Surfaces structured by LAO therefore represent ideal systems to study the dependence of protein adsorption on topography. We are able to visualize the created nanostructures with an AFM and successively adsorb the proteins in situ, rinse and image the new surface. The densities of adsorbed proteins on the nanostructured and neat surfaces are compared and we find that the protein arrangement depends on the underlying nanostructures, showing that proteins can ''sense'' the topography of surfaces at the nanometer scale. This result can be considered as the nanoscale analogous of the adsorption found for cell systems on micrometer structures.

Tuning Cell Adhesion on PTFE Surfaces by Laser Induced Microstructures

“…[4,5] A number of studies have demonstrated how the adhesion of cells to materials surfaces may be determined. Commonly peptides, in particular RGD-sequences, [6][7][8][9] and proteins like fibronectin, [10][11][12][13][14][15] albumin, [16] or extra cellular matrix proteins [17,18] have been used as coatings to improve the cell adhesion.…”

Bioadhesion of Biomaterials

“…Some reports suggest that the amount of protein adsorbed is not or very moderately affected by the surface roughness without conformational changes of protein (Cai et al 2006); while other reports reveal high augmentation of the proteins adsorbed and abrupt changes in their conformation upon adsorption (Han et al 2003). It was stated also that proteins with dimensions in the same order as the surface roughness are not conformationally altered by the surface, and proteins with dimensions much smaller or much larger change upon adsorption (Galli et al 2002). However, Fournier (1999) found no linear relationship between the surface roughness and protein adsorption.…”

Protein adsorption on materials surfaces with nano-topography

“…One of the key factors to solve this problem is to construct nanometer-scale groove structures with homogeneous surface chemical compositions. Galli et al [21,22] produced nanometer groove structures with dimensions similar to protein size on silicon and titanium surfaces by combining local anodic oxidation (LAO) and atomic force microscopy (AFM) techniques, which provided an effective basis to such research. They chose protein A and F-actin as two different model proteins.…”