Micro-structuring of polycarbonate-urethane surfaces in order to reduce platelet activation and adhesion

Abstract

In the development of new hemocompatible biomaterials, surface modification appears to be a suitable method in order to reduce the thrombogenetic potential of such materials. In this study, polycarbonate-urethane (PCU) tubes with different surface microstructures to be used for aortic heart valve models were investigated with regard to the thrombogenicity. The surface structures were produced by using a centrifugal casting process for manufacturing PCU tubes with defined casting mold surfaces which are conferred to the PCU surface during the process. Tubes with different structures defined by altering groove widths were cut into films and investigated under dynamic flow conditions in contact with porcine blood. The analysis was carried out by laser scanning microscopy which allowed for counting various morphological types of platelets with regard to the grade of activation. The comparison between plain and shaped PCU samples showed that the surface topography led to a decline of the activation of the coagulation cascade and thus to the reduction of the fibrin synthesis. Comparing different types of structures revealed that smooth structures with a small groove width (d ~ 3 μm) showed less platelet activation as well as less adhesion in contrast to a distinct wave structure (d ~ 90 μm). These results prove surface modification of polymer biomaterials to be a suitable method for reducing thrombogenicity and hence give reason for further alterations and improvements.

Real‐Time Visualization of Platelet Interaction With Micro Structured Surfaces

“…2C). This is in agreement to the literature thresholds for structure dimensions which have a negative impact on the hemocompatibility of the surface (3,18,21).…”

“…The chemical methods include all modifications of the material's chemistry as, for example, organic and inorganic coatings or bio-functionalization (9)(10)(11)(12)(13). Physical methods include all techniques which alter the surface properties by mechanical structuring of the surfaces, for example, random or regular structures in the micro-or nanometer range or the adjustment of a special roughness (3,7,(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). Ding et al…”

“…In summary, all research groups investigating this issue came to the result that surface structuring of blood-contacting foreign materials has a considerable influence on the surface properties in terms of hemocompatibility (3,7,(14)(15)(16)(17)(18)(19)(20)(21). Geometries in the range of the mean platelet diameter of 3 μm were proven to have a positive impact on the hemocompatibility, whereas larger geometries led to clotting on the surfaces (3,21).…”

Protein adsorption, platelet adhesion, and bacterial adhesion to polyethylene-glycol-textured polyurethane biomaterial surfaces

“…19,20 Recently, topographic approaches for controlling biological response have become increasingly common. 6,15 Numerous studies have demonstrated that micro-or nanostructured surfaces influence cell behaviors, 21,22 reduce platelet adhesion/activation, 23,24 and inhibit bacterial adhesion/ biofilm formation. [25][26][27][28][29] Among them, the ability to inhibit bacterial adhesion through topographic approach might be more attractive since the topographic approach does not require incorporating antibiotic agents into materials that might lead to antibiotic resistance of bacteria.…”

Physical Characterization and Platelet Interactions under Shear Flows of a Novel Thermoset Polyisobutylene-based Co-polymer

“…The surface roughness reported here may be mitigated by refining the manufacturing process. 68 Platelet adhesion on other valve polymer candidates (such as thermoplastic polyurethane, PCU, and silicone) has been reduced by surface smoothing of thermoplastic polyurethane with Argon plasma treatment, 69 transfer of a wave-like groove pattern to PCU tubes from a centrifugal casting mold, 70 and magnetic abrasive finishing of silicone rubber. 71 Optimization of xSIBS roughness using similar techniques will be explored in the future.…”