Narrow Results

In order to improve the nonthrombogenicity of chitin, a new monomer, N, N-dimethyl(β-hydroxyethyloxyethyl) ammonium propanesulfonate (DHAPS) was designed, synthesized and grafted onto the chitin membrane by using hexamethylene diisocyanate (HDI) as a coupling agent. Surface analysis of the grafted membranes by ATR-FTIR and XPS confirms that DHAPS has been successfully grafted onto the membrane surface. The platelet resistant property of the grafted membranes was evaluated by a platelet-rich plasma adhesion method. The results showed that platelet-adhesive resistance of the modified membrane has been greatly improved.

There have been a number of attempts to create a novel surface that reduces the adverse effects of blood interaction with material. Among various techniques, laser-induced surface modification is highly suitable for this purpose. The paper presents surface modification of PET using CO₂ pulsed laser. The changes in surface properties were investigated by scanning electron microscopy (SEM), attenuated total reflectance infrared spectroscopy (ATR-FTIR) and water drop contact angle measurements. The complicated microstructures on the PET surface were observed in SEM micrographs. ATR-IR spectra showed that the crystallinity decreased in the surface region as a result of laser irradiation. The water drop contact angle also decreased with increasing the laser pulses. The haemocompatibility of CO₂ laser irradiated PET was examined in vitro, evaluating its capability of inducing platelet adhesion in comparison with the unmodified PET. The number of adhered platelets was determined by platelet-rich plasma method and lactate dehydrogenase activity measurements. Platelet adhesion on the untreated PET was relatively high. Laser irradiation of PET surface reduced the number of adherent platelets and prevented platelet spreading on the surface. The extent of platelet adhesion was correlated to the number of laser pulses.

The taltanlum nitride films had been synthesized by the reactive magnetron sputtering which deals with the orthogonal design technology of the films including N₂ partial pressure rate, substrate temperature, sputtering pressure and sputtering current. The results showed that the adhesion between the film and substrate was influenced mainly by sputtering pressure and substrate temperature. The hardness of taltanlum nitride films was affected greatly by N₂ partial pressure. The hardness of the taltanlum nitride film was as high as about HK4000. The blood compatibility of the taltanlum nitride films were evaluated by clotting time measurement and platelet adhesion test. The blood compatibility of the TiN, Ta films and low temperature isotropic pyrolytic carbon (LTIC) also were evaluated for comparing. The result showed that the blood compatibility of taltanlum nitride was better than that of the TiN, Ta and LTIC.

Titanium oxide films doped with tantalum were synthesized on titanium and silicon wafer by sputtering deposition. The structure was investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Blood compatibility of the films was evaluated by clotting time measurement, platelet adhesion investigation and protein adsorption. In vivo experiment was further performed. The result showed that the Ta doped titanium oxide film has attractive blood compatibility which exceed low isotropic pyrolytic carbon. The mechanism of the behavior of blood compatibility of Ta doped film was discussed.