Papers by Keyword: Hemocompatibility

Abstract: TiO2, ZrO2 and titanium oxide in deficiency oxygen environment were used to modify the surface of biomedical NiTi stents. The coatings were prepared by vacuum deposition. The surface microstructures and characteristics, blood compatibility of the modified stents in simulated body fluids were assessed using scanning electron microscopy (SEM), hemolysis test, coagulation test and blood platelet adhesion test. The hemocompatiblity of the modified stents were all improved by layer coating. Enhancement of blood compatibility was believed to stem from the improved surface water affinity and hemolysis resistance of the layer, and titanium oxide in deficiency oxygen environment displayed better. This study indicated that layer coating was a promising effective modification method for improving the surface properties of biomedical NiTi alloy intravascular stents. As a coating materials，titanium oxide in deficiency oxygen environment was better than TiO2 and ZrO2.

Abstract: Materials used to make artificial vessels and hearts can cause thrombosis, thus hindering the development of these therapeutic aids. Endothelial cells (ECs) play a key role in thrombosis, so in this study, we used human umbilical vein endothelial cells (HUVEC) and tested the hemocompatibility of different biomaterials. We then measured the signal proteins MAPK (mitogen-activated protein kinase) and Nuclear Factor- kB (NF-κB) to investigate the correlation between their expression and the degree of hemocompatibility. The results showed that ECs in the polyurethane (PU-60) group had significantly more NF-κB than the negative control (p<0.5). To identify whether the increased expression of NF-κB was induced by MAPK activation, we investigated changes in phosphorylated MAPK. We found both MAPK and NF-κB are ideal indicators for evaluating the hemocompatibility of biomaterial.

Abstract: Hemocompatibility of a biomaterial is determined by the interactions between its surface and blood. Due to the complicated action mechanism, various effective ways and the multiple affective factors of the hemocompatibility, a comprehensive evaluation needs to be built instead of single index. Therefore, the platelet consumption ratio of 10 kinds of biomaterials including Ti6Al4V-TiC-DLC gradient coat material was studied based on image analysis method. Combined with the kinetic clotting time and the hemolysis ratio, the comprehensive hemocompatibility evaluation of the material is carried out based on the improved principal component analysis. First, linear transformation of negative index is carried out. Second, index is under a dimensionless using the logarithmic treatment, then to acquire all variants’ principal component and their characteristic vectors. Finally, comprehensive evaluation index of hemocompatibility is constructed. The improved principal component analysis avoids the effect of correlativity among indexes during anaphase evaluation, and can more correctly maintain the original information of indexes. Thus, the research provides a new idea to the comprehensive evaluation of Hemocompatibility.

Abstract: Rutile titanium oxide films were fabricated by reactive unbalanced magnetron sputtering. The blood compatibility is evaluated in vitro by clotting time and platelet adhesion measurement. The surface valence band electronic structure is gained by the XPS valence band spectra. The rutile titanium oxide films exhibit attractive hemocompatibility. The result of the valence band electronic structure of the films on the surface indicated that the rutile titanium oxide film represent an n-type semiconductor characteristics and the characters result in the prevention of the charge transfering between the blood and materials and overall excellent antithrombogenic properties.

Abstract: Piperazinyl-amide derivatives of N--(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. Their biological activity was evaluated in vitro, against human -thrombin, and in blood coagulation assay. The piperazinyl-amide derivatives were found to inhibit the activity of -thrombin in the micromolar range. The designed molecules were fixed on poly(ethylene terephthalate) (PET), and poly(butylene terephthalate) (PBT) by wet chemistry treatment (activation of hydroxyl chain-ends) and photochemistry (nitrene insertion by photoactivation of aromatic azide). The protocols were validated by X-ray photoelectron spectroscopy (XPS) and by radiochemical assay (liquid scintillation counting, LSC).

Abstract: The structural versatility of polyurethane based membranes is enhanced through the introduction of two soft segments to obtain new membranes with improved hemocompatibility. Crosslinked polyurethane/urea membranes with two soft segments were prepared by extending a polypropylene oxide-based tri-isocyanate terminated prepolymer (PU) with polybutadiene diol (PBDO). The ratio of PU to PBDO was 100/0 and 90/10. The membranes were characterised in terms of permeation towards O2 and CO2 and their hemocompatibility was evaluated through hemolysis and thrombosis experiments. It was found that the membrane with PBDO had the highest permeability to O2 and CO2 and it was non-hemolytic and less thrombogenic.

Abstract: Titanium oxide films were prepared by reactive magnetron sputtering using continuous or pulsed DC sputtering power. The results of the structure and vitro hemocompatibility analyses indicated that non-stoichiometric titanium oxide films possess better hemocompatibility than LTIC and that the hemocompatibility of the titanium oxide films are evidently improved with the increase of rutile phase. This can result from the lower interface tension between titanium oxide films and biological substances and lower ratio of dispersive and polar component of the surface energy.

Abstract: Ti-50.6 at.% Ni shape memory alloy was coated with tantalum using multi arc ion-plating technique with the aim to increase its radiopacity and biocompatibility. The surface characteristics were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results of XPS survey spectra show that a thin oxide film are formed inside tantalum coating as a result of natural passivation of Ta in atmosphere. The hemocompatibility was evaluated in vitro by clotting time and platelet adhesion measurement. The results of our study showed that the clotting time of tantalum was higher than that of the TiNi alloys and no sign of accumulation and only slight pseudopodium was observed on the tantalum coatings, suggesting that the tantalum coatings can improve the biocompatibility of TiNi alloy.