Lee J H, Lee H B
Department of Macromolecular Science, Hannam University, Daedeog Ku, Taejon, Korea.
J Biomed Mater Res. 1998 Aug;41(2):304-11. doi: 10.1002/(sici)1097-4636(199808)41:2<304::aid-jbm16>3.0.co;2-k.
A wettability gradient was prepared on lowdensity polyethylene (PE) sheets by treating them in air with a corona from a knife-type electrode the power of which increased gradually along the sample length. The PE surfaces oxidized gradually with the increasing corona power and a wettability gradient was created on the surfaces, as evidenced by the measurement of water contact angles, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. The wettability gradient surfaces prepared were used to investigate the adhesion behavior of platelets in the absence and presence of plasma proteins in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The platelets adhered to the wettability gradient surfaces along the sample length were counted and examined by scanning electron microscopy (SEM). It was observed that the platelet adhesion in the absence of plasma proteins increased gradually as the surface wettability increased along the sample length. The platelets adhered to the hydrophilic positions of the gradient surface also were more activated (possessed more pseudo pods as examined by SEM) than on the more hydrophobic ones. However, platelet adhesion in the presence of plasma proteins decreased gradually with the increasing surface wettability; the platelets adhered to the surface also were more activated on the hydrophobic positions of the gradient surface. This result is closely related to plasma protein adsorption on the surface. Plasma protein adsorption on the wettability gradient surface increased with the increasing surface wettability. More plasma protein adsorption on the hydrophilic positions of the gradient surface caused less platelet adhesion, probably due to platelet adhesion inhibiting proteins, such as high-molecular-weight kininogen, which preferably adsorbs onto the surface by the so-called Vroman effect. It seems that both the presence of plasma proteins and surface wettability play important roles for platelet adhesion and activation.
通过用刀型电极产生的电晕在空气中处理低密度聚乙烯（PE）片材，制备了润湿性梯度，该电极的功率沿样品长度逐渐增加。随着电晕功率的增加，PE表面逐渐氧化，并且在表面上形成了润湿性梯度，这通过水接触角的测量、衰减全反射模式下的傅里叶变换红外光谱以及化学分析用电子能谱得到了证实。制备的润湿性梯度表面用于研究在有无血浆蛋白存在的情况下，血小板在聚合物材料表面亲水性/疏水性方面的粘附行为。对沿样品长度粘附在润湿性梯度表面上的血小板进行计数，并通过扫描电子显微镜（SEM）进行检查。观察到在没有血浆蛋白的情况下，血小板粘附随着表面润湿性沿样品长度的增加而逐渐增加。与疏水性较强的位置相比，粘附在梯度表面亲水性位置的血小板也更具活性（通过SEM检查发现具有更多伪足）。然而，在有血浆蛋白存在的情况下，血小板粘附随着表面润湿性的增加而逐渐减少；粘附在表面的血小板在梯度表面的疏水性位置也更具活性。这一结果与血浆蛋白在表面的吸附密切相关。血浆蛋白在润湿性梯度表面的吸附随着表面润湿性的增加而增加。梯度表面亲水性位置上更多的血浆蛋白吸附导致更少的血小板粘附，这可能是由于血小板粘附抑制蛋白，如高分子量激肽原，其通过所谓的弗罗曼效应优先吸附到表面上。看来血浆蛋白的存在和表面润湿性对血小板的粘附和活化都起着重要作用。
