Surface modification of polypyrrole via affinity peptide: quantification and mechanism.
Surface modification of polypyrrole via affinity peptide: quantification and mechanism.
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DOI：
10.1039/c2tb00269h
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
J. Nickels;C. Schmidt
中科院分区：
文献类型：
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作者：
J. Nickels;C. Schmidt
导电聚合物聚吡咯（PPy）是一种令人兴奋的基础研究基质，用于研究外源电场存在下的细胞行为，并具有作为神经电极涂层的临床应用潜力。然而，典型的表面改性方法（例如，吡咯和吡咯衍生物的共聚、后聚合改性、用功能性生物分子掺杂）降低了导电性，从而降低了材料的实用性。在以前的工作中，一个12个氨基酸的肽，T59，进化到绑定到聚吡咯，并提供了一种新的表面改性的手段，不降低体积电导率。在目前的研究中，我们已经使用平衡结合分析和力谱来确定T59对PPy的亲和力为92.6 ± 21.4 nM，通过平衡结合分析，最大表面密度为5.1 ± 1.7 femtomoles/cm 2，并且该结合对的解离速率为2.5 s-1，计算的结合速率为2.6 × 107 M-1 s-1。这表明T59对PPy具有高亲和力，结合发生在快速平衡中。我们还提出了证据，支持T59的PPy结合的拟议机制，一个协会的天冬氨酸（D8）和离域的正电荷的骨干氧化PPy被指示为关键的相互作用。了解这种新的生物/合成界面的结合参数和机制是重要的，因为我们试图了解如何最好地利用聚吡咯基材料。
The conducting polymer, polypyrrole (PPy), is an exciting substrate for basic research to study cell behavior in the presence of exogenous electric fields and has potential for clinical application as a coating for neural electrodes. However, typical surface modification approaches (e.g., copolymerization of pyrrole and pyrrole derivatives, post-polymerization modification, doping with functional biomolecules) reduce the electrical conductivity and hence the utility of the material. In previous work, a 12 amino acid peptide, T59, was evolved to bind to PPy and provide a novel means of surface modification that does not reduce the bulk conductivity. In the current study, we have used equilibrium binding assays and force spectroscopy to determine that the affinity of T59 to PPy is 92.6 ± 21.4 nM, with a maximum surface density of 5.1 ± 1.7 femtomoles per cm2 by equilibrium binding assay, and that the off-rate of this binding pair is 2.5 s-1, with a calculated on-rate of 2.6 × 107 M-1 s-1. This suggests that T59 possesses a high affinity for PPy with binding that occurs in a rapid equilibrium. We also present evidence in support of a proposed mechanism of binding for T59 to PPy; an association of an aspartic acid (D8) and the delocalized positive charge on the backbone of oxidized PPy is indicated as the key interaction. Understanding the binding parameters and mechanism of this novel bio/synthetic interface is important as we try to understand how best to employ PPy-based materials.