论文标题
使用中子反射测定法
Equilibrium protein adsorption on nanometric vegetable-oil hybrid film/water interface using neutron reflectometry
论文作者
论文摘要
使用功能化的蓖麻油（ICO）和可交叉连接的用硅胶化基团形成了大约两个纳米厚度的纳米膜。这些杂种膜代表了在生物医学应用中替代常规聚合物材料的出色候选者，但是需要根据生物相容性进行优化，这与蛋白质的吸附高度相关。中子反射率已用于研究两种模型蛋白，牛血清白蛋白和溶菌酶在硅胶油（ICO） - 水界面上的吸附，在生理学离子强度和pH值和不同蛋白质浓度下的盐不存在和存在下。将这些测量值与空气水接口处的吸附。尽管盐在空气水和油水界面上以类似的程度增强了吸附，但与空气水界面相比，油膜的影响很大，在油水界面上的吸附三分三倍。在这些条件下，两种蛋白质的吸附层的浓度曲线表明多层吸附：外层的厚度（油侧）接近蛋白质分子的次要尺寸，〜30Å，表明与界面平行的长轴平行于侧向方向。内层延伸至55-60Å。有趣的是，在所有情况下，油膜的组成保持完整，而没有明显的蛋白质渗透到膜中。对这些纳米膜的最佳吸附，1.7-2.0 mg $ \ bullet $ m-2，可与最近使用石英晶体微生体和原子力显微镜在厚实的固体交联膜上获得的结果可比，特别表明在标准生理条件下这些ICO膜接口在标准生理学条件下在这些ICO膜接口处是非适用的。这些结果提供了有用的信息，以在直接的纳米级应用中阐述植物油基纳米膜或作为生物医学应用较厚的宏观膜制造中的前体膜。 2
Nanofilms of thickness of about two nanometers have been formed at the air-water interface using functionalized castor oil (ICO) with cross-linkable silylated groups. These hybrid films represent excellent candidates for replacing conventional polymeric materials in biomedical applications, but they need to be optimized in terms of biocompatibility which is highly related to protein adsorption. Neutron reflectivity has been used to study the adsorption of two model proteins, bovine serum albumin and lysozyme, at the silylated oil (ICO)-water interface in the absence and presence of salt at physiologic ionic strength and pH and at different protein concentrations. These measurements are compared to adsorption at the air-water interface. While salt enhances adsorption by a similar degree at the air-water and the oil-water interface, the impact of the oil film is significant, with adsorption at the oil-water interface three-to four-fold higher compared to the air-water interface. Under these conditions, the concentration profiles of the adsorbed layers for both proteins indicate multilayer adsorption: The thickness of the outer layer (oil-side) is close to the dimension of the minor axis of the protein molecule, ~ 30 Å, suggesting a side-way orientation with the long axis parallel to the interface. The inner layer extends to 55-60 Å. Interestingly, in all cases, the composition of oil film remains intact without significant protein penetration into the film. The optimal adsorption on these nanofilms, 1.7-2.0 mg$\bullet$m-2 , is comparable to the results obtained recently on thick solid cross-linked films using quartz crystal microbalance and atomic force microscopy, showing in particular that adsorption at these ICO film interfaces under standard physiological conditions is non-specific. These results furnish useful information towards the elaboration of vegetable oil-based nanofilms, in direct nanoscale applications or as precursor films in the fabrication of thicker macroscopic films for biomedical applications. 2
