Characterization of a planar poly(acrylic acid) brush as a materials coating for controlled protein immobilization
Characterization of a planar poly(acrylic acid) brush as a materials coating for controlled protein immobilization
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DOI：
10.1021/la053110y
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发表时间：
2006-03-28
期刊：
影响因子：
3.9
通讯作者：
Czeslik, C
中科院分区：
文献类型：
--
作者：
Hollmann, O;Czeslik, C
两种不同的蛋白质在一个平面的聚（丙烯酸）（PAA）刷的吸附研究作为一个功能的蛋白质溶液的离子强度应用全内反射荧光（TIRF）光谱。制备了接枝密度为0.11 nm（-2）的平面PAA刷，并使用X射线反射仪进行了表征。鸡蛋清溶菌酶和牛血清白蛋白（BSA）被用作模型蛋白，它们在中性pH值下分别具有净正电荷和负电荷。已经发现，这两种蛋白质强烈吸附在平面PAA刷在低离子强度。而溶菌酶在中性pH值下在静电吸引下与PAA刷相互作用，BSA在pH > 5下在静电排斥下结合。即使在pH = 8时，大量的BSA也被吸附到平面PAA刷上。此外，BSA吸附的可逆性进行了表征。BSA溶液的稀释导致BSA在短接触时间内从PAA刷上几乎完全解吸。当蛋白质溶液的离子强度增加到约100-200 mM时，平面PAA刷表现出很大程度上是蛋白质抗性的，而与蛋白质净电荷无关。这项研究的结果表明，PAA刷的盐依赖性蛋白质亲和力代表了一种独特的效果，必须通过一种新的蛋白质结合机制来解释。最近的模型的基础上，有人建议，释放抗衡离子是最可能的驱动力蛋白质吸附在PAA刷。在一般情况下，这项研究的特点是一个平面PAA刷作为一种新的材料涂层的蛋白质，其在生物技术应用中的使用似乎是有益的控制固定。
The adsorption of two different proteins at a planar poly(acrylic acid) (PAA) brush was studied as a function of the ionic strength of the protein solutions applying total internal reflection fluorescence (TIRF) spectroscopy. Planar PAA brushes were prepared with a grafting density of 0.11 nm(-2) and were characterized using X-ray reflectometry. Hen egg-white lysozyme and bovine serum albumin (BSA) were used as model proteins, which have a net positive and negative charge at neutral pH-values, respectively. It has been found that both proteins adsorb strongly at a planar PAA brush at low ionic strength. Whereas lysozyme interacts with a PAA brush under electrostatic attraction at neutral pH-values, BSA binds under electrostatic repulsion at pH > 5. Even at pH = 8, significant amounts of BSA are adsorbed to a planar PAA brush. In addition, the reversibility of BSA adsorption has been characterized. Dilution of a BSA solution leads to an almost complete desorption of BSA from a PAA brush at short contact times. When the ionic strength of the protein solutions is increased to about 100-200 mM, a planar PAA brush appears largely protein-resistant, regardless of the protein net charge. The results of this study indicate that the salt-dependent protein affinity of a PAA brush represents a unique effect that must be explained by a novel protein-binding mechanism. On the basis of a recent model, it is suggested that a release of counterions is the most probable driving force for protein adsorption at a PAA brush. In a general view, this study characterizes a planar PAA brush as a new materials coating for the controlled immobilization of proteins whose use in biotechnological applications appears to be rewarding.