Biocompatibility of Plasma-Treated Polymeric Implants

Abstract

Cardiovascular diseases are one of the main causes of mortality in the modern world. Scientist all around the world are trying to improve medical treatment, but the success of the treatment significantly depends on the stage of disease progression. In the last phase of disease, the treatment is possible only by implantation of artificial graft. Most commonly used materials for artificial grafts are polymer materials. Despite different industrial procedures for graft fabrication, their properties are still not optimal. Grafts with small diameters (<6 mm) are the most problematic, because the platelets are more likely to re-adhere. This causes thrombus formation. Recent findings indicate that platelet adhesion is primarily influenced by blood plasma proteins that adsorb to the surface immediately after contact of a synthetic material with blood. Fibrinogen is a key blood protein responsible for the mechanisms of activation, adhesion and aggregation of platelets. Plasma treatment is considered as one of the promising methods for improving hemocompatibility of synthetic materials. Another method is endothelialization of materials with Human Umbilical Vein Endothelial cells, thus forming a uniform layer of endothelial cells on the surface. Extensive literature review led to the conclusion that in this area, despite numerous studies there are no available standardized methods for testing the hemocompatibility of biomaterials. In this review paper, the most promising methods to gain biocompatibility of synthetic materials are reported; several hypotheses to explain the improvement in hemocompatibility of plasma treated polymer surfaces are proposed.

Keywords: biocompatibility; biomaterial; endothealization; endothelial cells; functionalization; hemocompatibility; plasma; polymer; surface properties; thrombosis; vascular graft.

Figure 1

Kinetics and phases of cell adhesion.

Figure 2

Nanostructured topography of the surface, that attracts (a) and repels (b) adhesion of platelets.

Figure 3

Illustration of the reorganization of cell actin skeleton structures, shape and attachment according to surface morphology.

Figure 4

Platelet adhesion on untreated (a) and oxygen plasma treated (b) poly(ethylene terephthalate (PET) polymer. Incubation was performed with shaking at 250 RPM.

Figure 5

Effect of different aging conditions on the wettability of surface of PET polymer treated in oxygen plasma glow for 30 s.