Characterization of protein adsorption onto silica nanoparticles: influence of pH and ionic strength.
Characterization of protein adsorption onto silica nanoparticles: influence of pH and ionic strength.
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DOI：
10.1007/s00396-015-3754-x
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发表时间：
2015
影响因子：
2.4
通讯作者：
Findenegg GH
中科院分区：
文献类型：
--
作者：
Meissner J;Prause A;Bharti B;Findenegg GH
在pH 2-11范围内，在三种不同的离子强度下，研究了溶菌酶和β-乳球蛋白在二氧化硅纳米颗粒（直径21 nm）上的吸附。由于这两种蛋白质有一个广泛不同的等电点（pI），静电相互作用与负二氧化硅表面导致不同的依赖性吸附pH值。溶菌酶（pI = 11），吸附水平随pH值的增加，并达到一个值对应于约两个紧密堆积的单层pH = pI。在pI附近的多层吸附区域，添加电解质导致吸附减少，这归因于在第一和第二吸附层中的蛋白质分子之间的吸引相互作用的屏蔽。对于β-乳球蛋白（pI ≥ 5），在pH 4下，在不存在盐的情况下，发现吸附量的显著最大值。这归因于在此pH下存在于溶液中的蛋白质的低聚物的吸附。在pH > pI时，盐对吸附量的影响发生逆转，其中蛋白质和表面都带负电荷。这种反转归因于排斥性蛋白质-表面和蛋白质-蛋白质相互作用的筛选。用Guggenheim-Anderson-De Boer（GAB）模型分析吸附等温线，该模型允许两种吸附状态（强结合蛋白和弱结合蛋白）。
The adsorption of lysozyme and ß-lactoglobulin onto silica nanoparticles (diameter 21 nm) was studied in the pH range 2–11 at three different ionic strengths. Since the two proteins have a widely different isoelectric point (pI), electrostatic interactions with the negative silica surface lead to a different dependence of adsorption on pH. For lysozyme (pI ≈ 11), the adsorption level increases with pH and reaches a value corresponding to about two close-packed monolayers at pH = pI. In the multilayer adsorption region near pI, added electrolyte causes a decrease in adsorption, which is attributed to the screening of attractive interactions between protein molecules in the first and second adsorbed layer. For ß-lactoglobulin (pI ≈ 5), a pronounced maximum of the adsorbed amount is found at pH 4 in the absence of salt. It is attributed to the adsorption of oligomers of the protein that exist in the solution at this pH. An inversion in the influence of salt on the adsorbed amount occurs at pH > pI, where the protein and the surface are both negatively charged. This inversion is attributed to the screening of the repulsive protein-surface and protein–protein interactions. The adsorption isotherms were analyzed with the Guggenheim–Anderson–De Boer (GAB) model, which allows for two adsorption states (strongly and weakly bound protein).