Volumetric interpretation of protein adsorption: Partition coefficients, interphase volumes, and free energies of adsorption to hydrophobic surfaces
Volumetric interpretation of protein adsorption: Partition coefficients, interphase volumes, and free energies of adsorption to hydrophobic surfaces
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DOI：
10.1016/j.biomaterials.2006.07.038
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发表时间：
2006-12-01
期刊：
影响因子：
14
通讯作者：
Vogler, Erwin A.
中科院分区：
文献类型：
--
作者：
Noh, Hyeran;Vogler, Erwin A.
使用SDS凝胶电泳作为分离和定量工具，实施测量蛋白质吸附的溶液耗尽方法。使用溶菌酶（15 kDa），α-淀粉酶（51 kDa），人血清白蛋白（66 kDa），凝血酶原（72 kDa），免疫球蛋白G（160 kDa），和纤维蛋白原（341 kDa）从水缓冲液吸附到疏水辛基琼脂糖和硅烷化玻璃颗粒的实验方法证明。解释性质量平衡方程来自一个模型，该模型基于蛋白质可逆地从本体溶液分配到将物理吸附表面与本体溶液分离的三维（3D）相间体积的想法。理论预期并适应所有蛋白质吸附到两个测试表面，这表明基本模型描述了蛋白质吸附的基本物理化学。应用质量平衡方程的实验数据量化分配系数P，相间体积V-1，和假设层的数量M所占据的蛋白质吸附在V-1。分配系数分别通过相间和本体溶液相w/v（mg/mL）浓度W-I和W-B的平衡比来量化蛋白质吸附亲合力，使得PW-I W-B。发现蛋白质是弱生物表面活性剂，具有45 < P < 520和非常低的表观吸附自由能-6RT <（Δ G（adphobic）（0）= -RT ln P）<-4RT。这些测量结果证实了从疏水性吸附界面能（张力测定法）获得的独立估计值，并且与通过疏水相互作用色谱法对相关蛋白质的热化学测量结果一致。分子量MW < 100 kDa的蛋白质在表面饱和时占据单层，而较大的蛋白质IgG和纤维蛋白原需要两层。(c)2006爱思唯尔有限公司保留所有权利。
The solution-depletion method of measuring protein adsorption is implemented using SDS gel electrophoresis as a separation and quantification tool. Experimental method is demonstrated using lysozyme (15 kDa), alpha-amylase (51 kDa), human serum albumin (66 kDa), prothrombin (72 kDa), immunoglobulin G (160 kDa), and fibrinogen (341 kDa) adsorption from aqueous-buffer solution to hydrophobic octyl-sepharose and silanized-glass particles. Interpretive mass-balance equations are derived from a model premised on the idea that protein reversibly partitions from bulk solution into a three-dimensional (3D) interphase volume separating the physical-adsorbent surface from bulk solution. Theory both anticipated and accommodated adsorption of all proteins to the two test surfaces, suggesting that the underlying model is descriptive of the essential physical chemistry of protein adsorption. Application of mass balance equations to experimental data quantify partition coefficients P, interphase volumes V-1, and the number of hypothetical layers M occupied by protein adsorbed within V-1. Partition coefficients quantify protein-adsorption avidity through the equilibrium ratio of interphase and bulk-solution-phase w/v (mg/mL) concentrations W-I and W-B, respectively, such that P W-I W-B. Proteins are found to be weak biosurfactants with 45 < P < 520 and commensurately low apparent free-energy-of-adsorption -6RT < (Delta G(ads phobic)(0) = -RT ln P) < -4RT. These measurements corroborate independent estimates obtained from interfacial energetics of phobic adsorption (tensiometry) and are in agreement with thermochemical measurements for related proteins by hydrophobic-interaction chromatography. Proteins with molecular weight MW < 100 kDa occupy a single layer at surface saturation whereas the larger proteins IgG and fibrinogen required two layers. (c) 2006 Elsevier Ltd. All rights reserved.