Unsworth Larry D, Sheardown Heather, Brash John L
Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ont., Canada L8S 4L7.
Biomaterials. 2005 Oct;26(30):5927-33. doi: 10.1016/j.biomaterials.2005.03.010. Epub 2005 Apr 26.
The mechanisms involved in the inhibition of protein adsorption by polyethylene oxide (PEO) are not completely understood, but it is believed that PEO chain length, chain density and chain conformation all play a role. In this work, surfaces formed by chemisorption of PEO-thiol to gold were investigated: the effects of PEO chain density, chain length (600, 750, 2000 and 5000 MW) and end-group (-OH, -OCH3) on protein adsorption from plasma are reported. Similar to previous single protein adsorption studies (L.D. Unsworth et al., Langmuir 2005;21:1036-41) it was found that, of the different surfaces investigated, PEO layers formed from solutions near the cloud point adsorbed the lowest amount of fibrinogen from plasma. Layers of hydroxyl-terminated PEO of MW 600 formed under these low solubility conditions showed almost complete suppression (versus controls) of the Vroman effect, with 20+/-1 ng/cm2 adsorbed fibrinogen at the Vroman peak and 6.7+/-0.6 ng/cm2 at higher plasma concentration. By comparison, Vroman peak adsorption was 70+/-20 and 50+/-3 ng/cm2, respectively, for 750-OCH3 and 2000-OCH3 layers formed under low solubility conditions; adsorption on these surfaces at higher plasma concentration was 16+/-9 and 12+/-3 ng/cm2. Thus in addition to the effect of solution conditions noted previously, the results of this study also suggest a chain end group effect which inhibits fibrinogen adsorption to, and/or facilitates displacement from, hydroxyl terminated PEO layers. Fibrinogen adsorption from plasma was not significantly different for surfaces prepared with PEO of molecular weight 750 and 2000 when the chain density was the same ( approximately 0.5 chains/nm2) supporting the conclusion that chain density may be the key property for suppression of protein adsorption. The proteins eluted from the surfaces after contact with plasma were investigated by SDS-PAGE and immunoblotting. A number of proteins were detected on the various surfaces including fibrinogen, albumin, C3 and apolipoprotein A-I. The blot responses were zero or weak for all four proteins of the contact system; some complement activation was observed on all of the surfaces studied.
聚环氧乙烷（PEO）抑制蛋白质吸附的机制尚未完全明确，但据信PEO的链长、链密度和链构象均发挥作用。在本研究中，对通过PEO-硫醇化学吸附到金表面形成的表面进行了研究：报告了PEO链密度、链长（600、750、2000和5000 MW）以及端基（-OH、-OCH3）对血浆中蛋白质吸附的影响。与之前的单一蛋白质吸附研究（L.D. Unsworth等人，《朗缪尔》2005年；21:1036 - 41）类似，研究发现，在所研究的不同表面中，由接近浊点的溶液形成的PEO层从血浆中吸附的纤维蛋白原量最低。在这些低溶解度条件下形成的分子量为600的羟基封端PEO层几乎完全抑制了（相对于对照）弗罗曼效应，在弗罗曼峰处吸附的纤维蛋白原为20±1 ng/cm²，在较高血浆浓度下为6.7±0.6 ng/cm²。相比之下，在低溶解度条件下形成的750 - OCH3和2000 - OCH3层的弗罗曼峰吸附量分别为70±20和50±3 ng/cm²；在较高血浆浓度下，这些表面的吸附量分别为16±9和12±3 ng/cm²。因此，除了先前指出的溶液条件的影响外，本研究结果还表明存在链端基效应，该效应抑制纤维蛋白原吸附到羟基封端的PEO层上和/或促进其从该层上的置换。当链密度相同时（约0.5条链/nm²），用分子量为750和2000的PEO制备的表面对血浆中纤维蛋白原的吸附没有显著差异，这支持了链密度可能是抑制蛋白质吸附的关键特性这一结论。通过SDS - PAGE和免疫印迹法对与血浆接触后从表面洗脱的蛋白质进行了研究。在各种表面上检测到了多种蛋白质，包括纤维蛋白原、白蛋白、C3和载脂蛋白A - I。接触系统的所有四种蛋白质的印迹反应均为零或较弱；在所有研究的表面上均观察到了一些补体激活现象。
