Papers by Keyword: Platelet Adhesion

Abstract: Silk fibroin (SF) has good biocompatibility and has been used to construct small caliber artificial blood vessels. As a vascular graft, the antithrombogenicity is the first important performance. The aim of this study was to evaluate the anticoagulant property of polyethylene glycol diglycidyl ether (PEG-DE) crosslinked and ethanol treated SF materials by investigating the platelet adhesion. Dacron and PTFE were parallel studied as the controls. Results showed that: the platelet adhesion ratios on the ethanol treated SF films were significantly lower than that on the Dacron and PTFE; the platelet adhesion ratios on the PEG-DE crosslinked SF films were higher than that on the ethanol treated SF films and slightly increased with increasing the proportion of the PEG-DE. But the platelet adhesion ratios on all of the PEG-DE crosslinked SF films were significantly lower than that on the controls.

Abstract: Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. It has been improved that TiO₂ has excellent hemocompatibility. In this study, TiO₂ nanoparticles was added into polytetrafluorethylen (PTFE) resin in order to enhance hemocompatibility of the organic coating. The surface hydrophobicity of the coatings was characterized by contact angle measurement. Systematic evaluation of hemocompatibility, including platelet adhesion and blood clotting, proved that TiO₂ nanoparticles composite PTFE coating have better hemocompatibility. It is suggested that TiO₂ nano particles can improve hemocompatibility of organic coating due to its passive surface and chemical stability.

Abstract: Aiming to develop a biomaterial with excellent biocompability, a novel β-cyclodextrin modified polylactic acid (PLA-β-CD) was synthesized by N-acylation reaction of MPLA (maleic anhydride modified poly(d,l-lactic acid)) using hydrophilic mono(6-(2-aminoethyl)-amino-6-deoxy)- β-cyclodextrin(β-CD-6-E) as acylating agent. Surface wettability and blood biocompatibility of PLA-β-CD were investigated. The tests indicated that the static water contact angle of PLA-β-CD was decreased from 76.7º to 72.1º comparing with PLA. The morphology of blood platelets adhered on the surface of PLA-β-CD was observed by scanning, and only a few platelets, round and not aggregated. The results revealed that the blood compatibility of PLA-β-CD was better than PLA.

Abstract: In this paper, the micro pits were fabricated on 316L stainless steel surface, and the influence of pits topography on the platelets adhesion was investigated. For initial steel, large platelets agglomeration and long pseudopodia are observed. It is found that the pits on stainless steel surface can effectively prevent pseudopodia spreading; as a result the aggregation of platelets is fully restrained. The resistance of platelets adhesion increase with the coverage rate of pits area () on total steel surface.

Abstract: Regular arrays of micro-pillars and nano-grooves structures on the silicon wafer are fabricated by using soft lithography, and the three dimension morphology of textured surface is observed by using scanning electron microscopy (SEM) and atomic force microscope (AFM). The static water contact angles are measured by using contact angle meter to characterize the wettabilities of these surfaces. To investigate how the presence of topography and the variations of wettability affect the haemocompatibility of textured surface contacted with blood, different patterned surfaces are designed and fabricated, and blood platelet adhesion test is carried out on these surfaces. The adhesion and coagulation of platelets are inspected by scanning electron microscopy (SEM). Experimental data presented in this paper indicate that different surface roughness and wettability are the important factors for blood platelet adhesion. The amount of adsorbed blood platelet is low on textured surfaces, compared with that on the flat surface. Especially, there is no coagulation and activation on the surface with nanometer grooves. That is to say, the superhydrophobic surface is apt to decrease blood platelet adhesion. The study suggests that surface with suitable wettabililty and textured structures exhibits superior blood compatibility.

Abstract: Diamond-Like carbon (DLC) films were prepared under different bias voltage by direct current magnetic filter cathode vacuum arc deposition (DC-MFCVAD). Bias voltages changed from 0 to -200 V. The study intends to investigate the effect on the properties of DLC films for biomedical applications. X-ray photoelectron spectrum (XPS) was used to investigate composition of the films. Nano-scratch tests were used to characterize effects of bias voltage to adhesion. Furthermore, the wettability of the DLC films was investigated by contact angle measurements using four common liquids. Finally, platelet adhesion experiments were done to evaluate the interaction of blood with DLC films. The results showed that the adhesion, wettability and hemo-compatibility of DLC films were affected by bias voltage.

Abstract: Lactate dehydrogenase (LDH) and enzyme-linked immunosorbent assay (ELISA) have attracted much attention recently for the evaluation of blood compatibility of biomaterials due to their convenience and quantifiability. In this paper, the use of LDH and ELISA is described for in situ investigation of platelet behavior on biomaterial surfaces, including quantification of platelet adhesion and platelet activation, after suitable testing conditions have been established. The material samples investigated in these tests included low temperature isotropic carbon (LTIC), Ti-O films, and phosphorus- and aluminum-doped TiO2 films. The evaluation results show that the lowest platelet adhesion and activation are observed on phosphorus-doped TiO2 films while the highest platelet adhesion and activation are observed on LTIC. In addition, conventional platelet adhesion experiments were performed for comparison, and yielding similar evaluation results as LDH and ELISA. It is suggested that LDH and ELISA tests can be successfully applied to evaluate the blood compatibility of biomaterials and can show many advantages, such as quantification, reliability and objectivity, compared with conventional platelet adhesion test.

Abstract: Ammonia implanted silicon was performed by using plasma immersion ion implantation (PIII) to form a silicon nitride films. Blood compatibility of the prepared samples was investigated by platelets adhesion testing. It showed less activation i.e. lower thrombosis risks occurs on the prepared silicon nitride films than control silicon sample. The enhanced blood compatibility of the material is attributed to the modified surface properties such as hydrophilicity from thermodynamic adsorption perspective, which is related to surface chemical bonding states achieved by PIII process.

Abstract: Amorphous carbon (a-C) and carbon nitrogen (a-CN) films were synthesized using plasma immersion ion implantation and deposition (PIII-D) under different N2 flow at room temperature (R.T.). Lifshitz-van der Waals/acid-base approach (LW-AB) was introduced in order to study films’ surface energy deeply. The results showed that the capability of the surface of the film on receive electron changed with N2 flow, which effected platelet adhesion of film strongly. Hall effects tests were employed to characterize the electrical properties of the films. The results showed that the as-deposited films exhibited n-type semiconductor characteristic, and carrier concentration of the films decreased with N2 flow increasing. Raman spectra with 514nm laser-source were employed to analyze the structural of the films.

Abstract: Platelet adhesion and activation restrict the clinical applicability of blood-contacting biomaterial because platelet-biomaterial interaction can result in the formation of a haemostatic plug or thrombus. In this study we used LDH (lactate dehydrogenase) tests to evaluate the adsorption behavior of platelets on material surfaces. Enzyme immunoassay (EIA) was applied to evaluate platelet activation using a special monoclonal antibody directly binding to the Pselectin on the activated platelet membrane. The results show compared with the conventional detecting tools of platelet adhesion / activation such as optical microscopy. LDH (lactate dehydrogenase) testing and EIA (enzyme immunoassay) are surface-sensitive methods for the investigation of various aspects of platelet adsorption and activation on different biomaterials.