Fabrication And Study Of Super-hydrophobic Surface And Its Blood Compatibility

Biomaterial's blood compatibility is that biomaterial surface has the ability to anticoagulate and effect on hemolysis, platelet function reduction, leucocyte decreasing, alexin activation and blood physiological function. Biomaterial's blood compatibility has close relation to material surface properties such as surface wettability, surface energy, interface tension and surface charge. Accordingly, surface modification is regarded as a significant means to improve the anticoagulation of biomaterials. It's a great task for researchers to thoroughly study the interactions of biomaterial surface with blood and further recognize the surface modification mechanism of anticoagulation materials. For improving the blood compatibility of the materials, surface micro-pattern fabrication technology is a significant method to control the adhesion and proliferation of endothelial cells on materials. Nowadays, the surface micro-pattern technique has become an important modification method for biomaterials.In this paper, PDMS square pillar arrays surface, parallel grating surface, papilla surface were fabricated by soft lithography. Changing the geometric parameters the different patterns were fabricated. The Scanning electron microscope (SEM) images showed that the fabricated samples had high fidelity. The contact angles of relevant micro-patterns were tested. In addition, the surface energy, including the polar component, the dispersive component and the interface tension and etc were calculated. The result indicated that the surface with micro-pattern is preferable super-hydrophobic and the ratio of polar component and dispersive component increased. At the same time the interface tension between the biomaterials and biological substances decreased sharply. It's found that micro-nano-binary structure (NMBs) on the materials surface had great effect on wettability by analyzing the contact angle results of grating surface and papilla surface.In this way, blood compatibility refers to many factors and its mechanism is also complex, so single and isolate parameter can't describe biomaterial's blood compatibility. In this paper the interactions of biomaterials with blood are systematically analyzed by studying platelet adhesion, dynamic clotting time, hemolysis and micro-patterns surface properties. The result of biomaterials' blood compatibility study showed that:(1) By studying the platelet adhesion on three kinds of materials with different topographies, it was found that the platelet adhesion reduced with the increasing of materials' hydrophobicity. Especially the micro-nano-binary structure (NMBs) on the materials surface can efficiently reduce the platelet adhesion.(2) By study on dynamic clotting time of three materials with different topographies, variant materials intervention is sure to activate coagulation way and shorten the coagulation time. Increasing hydrophobicity can prolong coagulation time. The effect of micro-nano-binary structure (NMBs) on improving anticoagulation was quite remarkable.(3) With observing hemocyte's variation, the hemolysis rate of three kinds of materials with different topographies was all below 5% and attained the standard of biomaterials. Increasing materials' hydrophobicity can reduce hemolysis rate.All the results above show that micro-pattern surfaces have remarkable blood compatibility and can widely apply in surface modification of biomaterials.