Effects of Plasma Proteins on Staphylococcus epidermidis RP62A Adhesion and Interaction with Platelets on Polyurethane Biomaterial Surfaces (original) (raw)
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Journal of Biomaterials and Nanobiotechnology, 2012
Plasma proteins influence the initial adhesion of bacteria to biomaterials as well as interactions between bacteria and blood platelets on blood-contacting medical devices. In this paper, we study the effects of three human plasma proteins, albumin, fibrinogen (Fg), and fibronectin (Fn), on the adhesion of Staphylococcus epidemidis RP62A to polyurethane biomaterial surfaces, and also address how these three proteins affect bacterial interactions with human platelets on materials. Measurements of bacterial adhesion on polymer surfaces pre-adsorbed with a variety of proteins demonstrate that Fn leads to increased bacterial adhesion, with the order of effectiveness being Fn Fg > albumin. Immuno-AFM (atomic force microscopy) was used to assess the Fn adsorption/activity on surfaces and bacterial cell membranes by looking at molecular scale events. A correlation between molecular scale Fn adsorption and macroscale bacterial adhesion was observed, with an increased numbers of Fn-receptor recognition events measured on cell surfaces as compared to Fg-receptor recognition events, suggesting Fn is an important protein in bacterial adhesion. Monoclonal antibodies recognizing either the carboxyl-terminus or amino-terminus of Fn were coupled to AFM probes and used to assess the orientation of Fn adsorbed on a surface, with an increased amount of Fn carboxyl-terminus availability corresponding to higher bacterial adhesion. Interactions between bacteria and platelets were demonstrated with fluorescence and AFM imaging on the polyurethane surfaces, with albumin inhibiting bacteria-platelet interaction and platelet activation, and both Fg and Fn promoting adhesion of bacteria to platelets and apparent platelet activation, resulting in bacteria/platelet aggregation.
Current microbiology, 2015
The influence of soluble and immobilized plasma, albumin, and fibronectin (Fn) on the adhesion of three Staphylococcus epidermidis strains to polystyrene was investigated. Both soluble and immobilized plasma and albumin cause to 7-fold reduction of the amounts of adhered cells, regardless of the strain used. The soluble Fn exhibited the adhesion for one strain and did not affect the bacterial sorption for remaining strains, whereas on Fn-coated polystyrene two of the three strains showed about 1.5-fold increase in the number of adsorbed bacteria. The plasma- and albumin-coated surfaces became much more hydrophilic as the contact angle changed from 78 ± 2° for control to 18 ± 2° for plasma and 21 ± 3° for albumin. The ligand-receptor specific interactions strains S. epidermidis with Fn-coated surfaces were proved by measuring the adhesion forces between cell surface and Fn-coated AFM tip. The surface roughness measured using AFM after the plasma and proteins immobilization was change...
Journal of Biomedical Materials Research Part A, 2005
Ten specially synthesized polyurethanes (PUs) were used to investigate the effects of surface properties on platelet adhesion. Surface composition and hydrophilicity, fibrinogen (Fg) and von Willebrand's factor (vWf) adsorption, monoclonal anti-Fg binding, and platelet adhesion were measured. PUs preadsorbed with afibrinogenemic plasma or serum exhibited very low platelet adhesion, while adhesion after preadsorption with vWf deficient plasma was not reduced, showing that Fg is the key plasma protein mediating platelet adhesion under static conditions. Platelet adhesion to the ten PUs after plasma preadsorption varied greatly, but was only partially consistent with Fg adsorption. Thus, while very hydrophilic PU copolymers containing PEG that had ultralow Fg adsorption also had very low platelet adhesion, some of the more hydrophobic PUs had relatively high Fg adsorption but still exhibited lower platelet adhesion. To examine why some PUs with high Fg ad-sorption had lower platelet adhesion, three monoclonal antibodies (mAbs) that bind to sites in Fg thought to mediate platelet adhesion were used. The antibodies were: M1, specific to ␥-chain C-terminal; and R1 and R2, specific to RGD containing regions in the ␣-chain N-and C-terminal, respectively. Platelet adhesion was well correlated with M1 binding, but not with R1 or R2 binding. When these mAbs were incubated with plasma preadsorbed surfaces, they blocked adhesion to variable degrees. The ability of the R1 and R2 mAbs to partially block adhesion to adsorbed Fg suggests that RGD sites in the alpha chain may also be involved in mediating platelet adhesion and act synergistically with the C-terminal of the ␥-chain.
Direct observation of interaction between proteins and blood-compatible polymer surfaces
The adhesion force between blood-compatible polymer ͑poly͑2-methoxyethyl acrylate: PMEA͒ and proteins ͑fibrinogen and bovine serum albumin ͑BSA͒͒ were measured by atomic force microscopy. The PMEA surface showed almost no adhesion to native protein molecules, whereas non-blood-compatible poly͑n-butyl acrylate͒: PBA strongly adhered to proteins. Interestingly, adhesion did appear between PMEA and proteins when the proteins were denatured. In all cases, these trends were not affected by the conditions of the solution. Combining the results with previous reports, the authors conclude that interfacial water molecules play a critical role in the protein resistance of PMEA.
Platelet adhesion studies on dipyridamole coated polyurethane surfaces
European Cells and Materials, 2003
Surface modification of polyurethanes (PUs) by covalent attachment of dipyridamole (Persantin ®) is known to reduce adherence of blood platelets upon exposure to human platelet rich plasma (PRP). This effect was investigated in further detail. First platelet adhesion under static conditions was studied with four different biomaterial surfaces: untreated PU, PU immobilised with conjugate molecule 1, PU immobilised with conjugate molecule 2, and PU immobilised with conjugate molecule 3. In PU immobilised with 1 dipyridamole is directly linked to the surface, in PU immobilised with 2 there is a short hydrophilic spacer chain in between the surface and the dipyridamole, while conjugate molecule 3 is merely the spacer chain. Scanning electron microscopy (SEM) was used to characterise platelet adhesion from human PRP under static conditions, and fluorescence imaging microscopy was used to study platelet adhesion from whole blood under flow. SEM experiments encompassed both density measurements and analysis of the morphology of adherent platelets. In the static experiments the surface immobilised with 2 showed the lowest platelet adherence. No difference between the three modified surfaces emerged from the flow experiments. The surfaces were also incubated with washed blood platelets and labeled with Oregon-Green Annexin V. No capture of Oregon-Green Annexin V was seen, implying that the adhered platelets did not expose any phosphatidyl serine at their exteriour surface.
Eur Cell Mater, 2004
This article reviews the mechanisms of bacterial adhesion to biomaterial surfaces, the factors affecting the adhesion, the techniques used in estimating bacteria-material interactions and the models that have been developed in order to predict adhesion. The process of bacterial adhesion includes an initial physicochemical interaction phase and a late molecular and cellular one. It is a complicated process influenced by many factors, including the bacterial properties, the material surface characteristics, the environmental factors, such as the presence of serum proteins and the associated flow conditions. Two categories of techniques used in estimating bacteria-material interactions are described: those that utilize fluid flowing against the adhered bacteria and counting the percentage of bacteria that detach, and those that manipulate single bacteria in various configurations which lend themselves to more specific force application and provide the basis for theoretical analysis of the receptor-ligand interactions. The theories that are reviewed are the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the thermodynamic approach and the extended DLVO theory. Over the years, significant work has been done to investigate the process of bacterial adhesion to biomaterial surfaces, however a lot of questions still remain unanswered.
Acta Biomaterialia, 2019
A dual functional polyurethane (PU) film that mimics aspects of blood vessel inner surfaces by combining surface texturing and nitric oxide (NO) release was fabricated through a soft lithography two-stage replication process. The fabrication of submicron textures on the polymer surface was followed by solvent impregnation with the NO donor, S-nitroso-N-acetylpenicillamine (SNAP). An in vitro plasma coagulation assay showed that the biomimetic surface significantly increased the plasma coagulation time and also exhibited reduced platelet adhesion and activation, thereby reducing the risk of blood coagulation and thrombosis. A contact activation assay for coagulation factor XII (FXII) demonstrated that both NO release and surface texturing also reduced FXII contact activation, which contributes to the inhibition of plasma coagulation. The biomimetic surface was also evaluated for bacterial adhesion in plasma and results demonstrate that this combined strategy enables a synergistic effect to reduce bacterial adhesion of Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa microorganisms. The results strongly suggest that the biomimetic modification with surface texturing and NO release provides an effective approach to improve the biocompatibility of polymeric materials in combating thrombosis and microbial infection.
Reduction of Bacterial Adhesion to Biocompatible Polymer Surfaces Via Plasma Processing
Plasma processing of the surfaces of biomaterials is interesting because it enables modification of the characteristics of a surface without affecting bulk properties. In addition, the results are strongly influenced by the conditions of the treatment. Therefore, by adjusting the plasma parameters it is possible to tailor the surface properties to best fulfill the requirements of a given application. In this work, polyurethane substrates have been subjected to sulfur hexafluoride glow discharge plasmas. The influences of different SF 6 plasma exposure times and pressures on the adhesion of Staphylococcus aureus and Pseudomonas aeruginosa to the polymer have been investigated. The wettability and surface free energy have been evaluated via contact angle measurements. At low pressure (6.7 Pa) the contact angle decreases with increasing exposure time in the 180 s to 540 s interval, but at higher pressure (13.3 Pa) it increases as a function of the same variable. Bacterial adhesion has been quantified from in vitro experiments by determining the growth of colonies on Petri dishes treated with agar nutrient. It has been observed that the surface properties play an important role in microbe adhesion. For instance, the density of adhered P. aeruginosa decreased as the surface contact angle increased. S. aureus preferred to adhere to hydrophobic surfaces.