Interpretation of Protein Adsorption:  Surface-Induced Conformational Changes

Abstract

Protein adhesion plays a major role in determining the biocompatibility of materials. The first stage of implant integration is the adhesion of protein followed by cell attachment. Surface modification of implants (surface chemistry and topography) to induce and control protein and cell adhesion is currently of great interest. This communication presents data on protein adsorption (bovine serum albumin and fibrinogen) onto model hydrophobic (CH(3)) and hydrophilic (OH) surfaces, investigated using a quartz crystal microbalance (QCM) and grazing angle infrared spectroscopy. Our data suggest that albumin undergoes adsorption via a single step whereas fibrinogen adsorption is a more complex, multistage process. Albumin has a stronger affinity toward the CH(3) compared to OH terminated surface. In contrast, fibrinogen adheres more rapidly to both surfaces, having a slightly higher affinity toward the hydrophobic surface. Conformational assessment of the adsorbed proteins by grazing angle infrared spectroscopy (GA-FTIR) shows that after an initial 1 h incubation few further time-dependent changes are observed. Both proteins exhibited a less organized secondary structure upon adsorption onto a hydrophobic surface than onto a hydrophilic surface, with the effect observed greatest for albumin. This study demonstrates the ability of simple tailor-made monochemical surfaces to influence binding rates and conformation of bound proteins through protein-surface interactions. Current interest in biocompatible materials has focused on surface modifications to induce rapid healing, both of implants and for wound care products. This effect may also be of significance at the next stage of implant integration, as cell adhesion occurs through the surface protein layer.

Protein Adsorption on Nano-scaled, Rippled TiO2 and Si Surfaces

“…This eventually results in an alignment of the proteins across the ripple backbones, which increases the contact area between neighboring proteins. Protein-protein interaction leading to an increased surface coverage is also described by Roach et al [3]. Although we observed the described adsorption behavior on short-wavelength ripples only on Si surfaces, we assume a similar effect for TiO 2 .…”

“…This in turn is mediated by protein adsorption on the surface of the corresponding device [1][2][3]. An improvement and acceleration of the healing after surgical intervention would cause a tremendous enhancement of life quality.…”

Evaluation of Protein Adsorption on Atmospheric Plasma Deposited Coatings Exhibiting Superhydrophilic to Superhydrophobic Properties

“…There has, however, been relatively few reports on protein adsorption measurements on highly hydrophobic or superhydrophobic (h [ 150°) surfaces. Some researchers report on the adsorption of protein on superhydrophobic surfaces [18] while some report on non-adsorbent properties on these surfaces [19,20]. Roach et al studied the interaction of proteins on hydrophilic and superhydrophobic porous thermally modified silica [20].…”

“…Some researchers report on the adsorption of protein on superhydrophobic surfaces [18] while some report on non-adsorbent properties on these surfaces [19,20]. Roach et al studied the interaction of proteins on hydrophilic and superhydrophobic porous thermally modified silica [20]. In their study a reduction in the level of BSA adsorption was observed on the superhydrophobic silica substrate material when compared with hydrophilic substrates.…”

Penetration and Saturation of Lysozyme in Phospholipid Bilayers

“…7 The adsorption of proteins to lipid layers is recognized as the first event following the implantation of biomaterials and has been shown to play an important role in determining subsequent events such as thrombus formation, foreign body reaction, and other undesirable responses. 8,9 The function of proteins is realized by their residues, whose capability is greatly affected by their local environment. It is of great importance to study the distribution of proteins in lipid membranes.…”