Wittemann Alexander, Ballauff Matthias
Physikalische Chemie I, Universität Bayreuth, Universitaetsstrasse 30, D-95440 Bayreuth, Germany.
Anal Chem. 2004 May 15;76(10):2813-9. doi: 10.1021/ac0354692.
The adsorption of bovine serum albumin (BSA), bovine beta-lactoglobulin, and bovine pancreatic ribonuclease A onto spherical polyelectrolyte brushes (SPB) is reported. The SPB consist of narrowly distributed poly(styrene) core particles (diameter approximately 100 nm) onto which linear chains of anionic polyelectrolytes are grafted. The polyelectrolyte shell consists of either the weak polyelectrolyte poly(acrylic acid) or the strong polyacid poly(styrenesulfonate). The SPB particles are dispersed in H(2)O at room temperature. The secondary structure of the proteins was investigated by Fourier transform infrared spectroscopy in transmission mode before and during adsorption to these colloidal brushes. The alpha-helix and beta-sheet content of the proteins was nearly fully retained in the adsorbed state for all systems. Only in the case of BSA interacting with poly(styrenesulfonic) brushes could a slight loss of alpha-helix structure be observed. As the interaction of SPB and proteins can be controlled by the ionic strength in the buffer, additional experiments were performed to release the adsorbed protein. The amount of released protein was quantified and was found to be strongly dependent on the kind of protein and brush used. The secondary structure of the released proteins could be analyzed as well. An almost full preservation of secondary structure was found. This demonstrates that SPB are well-suited to immobilize proteins. The SPB can be charged and decharged under retention of the secondary structure of the biomolecules.
报道了牛血清白蛋白（BSA）、牛β-乳球蛋白和牛胰腺核糖核酸酶A在球形聚电解质刷（SPB）上的吸附情况。SPB由分布狭窄的聚（苯乙烯）核颗粒（直径约100nm）组成，阴离子聚电解质的线性链接枝在其上。聚电解质壳层由弱聚电解质聚丙烯酸或强聚酸聚苯乙烯磺酸盐组成。SPB颗粒在室温下分散于水中。在蛋白质吸附到这些胶体刷之前和过程中，通过傅里叶变换红外光谱透射模式研究了蛋白质的二级结构。对于所有体系，蛋白质的α-螺旋和β-折叠含量在吸附状态下几乎完全保留。仅在BSA与聚苯乙烯磺酸刷相互作用的情况下，可观察到α-螺旋结构略有损失。由于SPB与蛋白质的相互作用可通过缓冲液中的离子强度来控制，因此进行了额外实验以释放吸附的蛋白质。对释放的蛋白质数量进行了定量，发现其强烈依赖于所用蛋白质和刷的种类。也对释放蛋白质的二级结构进行了分析，发现二级结构几乎完全保留。这表明SPB非常适合固定蛋白质。在保留生物分子二级结构的情况下，SPB可以进行充电和放电。
