Effects of surface wettability and contact time on protein adhesion to biomaterial surfaces

Abstract

Atomic force microscopy (AFM) was used to directly measure the adhesion forces between three test proteins and low density polyethylene (LDPE) surfaces treated by glow discharge plasma to yield various levels of water wettability. The adhesion of proteins to the LDPE substrates showed a step dependence on the wettability of surfaces as measured by the water contact angle (θ). For LDPE surfaces with θ > ∼60-65°, stronger adhesion forces were observed for bovine serum albumin, fibrinogen and human FXII than for the surfaces with θ < 60°. Smaller adhesion forces were observed for FXII than for the other two proteins on all surfaces although trends were identical. Increasing the contact time from 0 to 50 s for each protein-surface combination increased the adhesion force regardless of surface wettability. Time varying adhesion data was fit to an exponential model and free energies of protein unfolding were calculated. This data, viewed in light of previously published studies, suggests a 2-step model of protein denaturation, an early stage on the order of seconds to minutes where the outer surface of the protein interacts with the substrate and a second stage involving movement of hydrophobic amino acids from the protein core to the protein/surface interface.Impact statement-The work described in this manuscript shows a stark transition between protein adherent and protein non-adherent materials in the range of water contact angles 60-65°, consistent with known changes in protein adsorption and activity. Time-dependent changes in adhesion force were used to calculate unfolding energies relating to protein-surface interactions. This analysis provides justification for a 2-step model of protein denaturation on surfaces.

Direct-write assembly of 3D scaffolds using colloidal calcium phosphates inks

“…It has been shown that low cell adhesion strength is related to the dispersive component of SFE [21]. Previous works also demonstrated that: the more hydrophilic the material the more cells will adhere on the surface [22,23]. In this study both groups of scaffolds (β-TCP and BCP) presented a larger polar component compared to the apolar one.…”

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

“…Protein adsorption is influenced by the particular physico-chemical properties of the biomaterial surface which include chemistry, wettability; charge, and surface morphology [8]. The wettability of a material surface is considered to be one of the most influential parameters affecting protein adsorption with numerous studies in particular investigating protein adsorption and cellular adhesion on surfaces with a designed wettability gradient [9][10][11][12]. It is generally considered that proteins tend to adsorb more favourably onto hydrophobic than hydrophilic surfaces.…”

“…It is generally considered that proteins tend to adsorb more favourably onto hydrophobic than hydrophilic surfaces. Both Lee [13] and Xu [12] treated polyethylene material with a glow discharge plasma to produce surfaces with a wettability gradient for the study of albumin and fibrinogen (Fg) adsorption. These studies showed an increased amount of protein adsorption on hydrophobic surfaces and in the latter case, higher protein adhesion forces as surface hydrophobicity increased.…”

Improved Wettability Increases Osteoblastic Adhesion on Hydroxyapatite

“…A-type carbonate apatite, corresponding to a location of carbonate ions at monovalent anionic OH -sites, had lower wettability, lower cell spreading, and similar cell proliferation compared with HA. Surface wettability on several biomaterials other than apatite affects cell adhesion on polymer 16 , glass microscope slides 17 , yttria partially stabilized zirconia 18 , poly (methyl methacrylate) 13 , and titanium 14,19 . Despite the differences in substrates or methods for the improvement of surface wettability, changes in the surface wettability of biomaterials brought out advantages in cellular behaviors such as attachment and spreading.…”