Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
Phys Chem Chem Phys. 2011 Oct 21;13(39):17599-605. doi: 10.1039/c1cp20663j. Epub 2011 Sep 5.
We present an investigation of β-lactoglobulin adsorption onto spherical polyelectrolyte brushes (SPBs) by small angle X-ray scattering (SAXS). The SPB consists of a polystyrene core onto which long chains of poly(styrene sulfonate) are grafted. The amount and the distribution of proteins adsorbed in the brush layer at low ionic strength can be derived from SAXS. The analysis of the SAXS data reveals additionally that some of the protein molecules form aggregates of about six monomers in the adsorbed state. Furthermore, the position and the amount of slightly bound protein can be detected by the combination of the SAXS results and the SPB loading after extensive ultrafiltration. The total amount of adsorbed protein is compared to data derived from isothermal titration calorimetry. The comparison of both sets of data demonstrates that the protein molecules in the inner layers of the spherical polyelectrolyte brush are firmly bound. Proteins located in the outer layers are only weakly bound and can be washed out by prolonged ultrafiltration.
我们通过小角 X 射线散射（SAXS）研究了β-乳球蛋白在球形聚电解质刷（SPB）上的吸附。SPB 由聚苯乙烯核组成，其上接枝了长链聚苯乙烯磺酸盐。在低离子强度下，刷层中吸附的蛋白质的数量和分布可以通过 SAXS 得出。对 SAXS 数据的分析还表明，一些蛋白质分子在吸附状态下形成大约六个单体的聚集体。此外，通过 SAXS 结果和 SPB 负载的组合，可以检测到少量结合的蛋白质的位置和数量，经过广泛的超滤处理。吸附的总蛋白量与从等温滴定量热法得出的数据进行了比较。这两组数据的比较表明，球形聚电解质刷内层的蛋白质分子被牢固地结合。位于外层的蛋白质仅被弱结合，可以通过长时间的超滤被洗脱出来。
