Fraunhofer-Institute for Applied Solid State Physics, Tullastr. 72, Freiburg 79108, Germany.
Biomaterials. 2011 Oct;32(30):7325-32. doi: 10.1016/j.biomaterials.2011.06.052. Epub 2011 Jul 8.
Immobilization of proteins on a solid electrode is to date done by chemical cross-linking or by addition of an adjustable intermediate. In this paper we introduce a concept where a solid with variable surface properties is optimized to mediate binding of the electron-transfer protein Cytochrome c (Cyt c) by mimicking the natural binding environment. It is shown that, as a carbon-based material, boron-doped diamond can be adjusted by simple electrochemical surface treatments to the specific biochemical requirements of Cyt c. The structure and functionality of passively adsorbed Cyt c on variously terminated diamond surfaces were characterized in detail using a combination of electrochemical techniques and atomic force microscopy with single-molecule resolution. Partially oxidized diamond allowed stable immobilization of Cyt c together with high electron transfer activity, driven by a combination of electrostatic and hydrophobic interactions. This surface mimics the natural binding partner, where coarse orientation is governed by electrostatic interaction of the protein's dipole and hydrophobic interactions assist in formation of the electron transfer complex. The optimized surface mediated electron transfer kinetics around 100 times faster than those reported for other solids and even faster kinetics than on self-assembled monolayers of alkanethiols.
迄今为止，将蛋白质固定在固体电极上是通过化学交联或添加可调节的中间物来实现的。在本文中，我们介绍了一种概念，即通过模拟自然结合环境，优化具有可变表面性质的固体来介导电子转移蛋白细胞色素 c（Cyt c）的结合。事实证明，作为一种基于碳的材料，掺硼金刚石可以通过简单的电化学表面处理，根据 Cyt c 的特定生化要求进行调整。使用电化学技术和原子力显微镜（具有单分子分辨率）的组合，详细研究了各种末端金刚石表面上被动吸附 Cyt c 的结构和功能。部分氧化的金刚石允许 Cyt c 的稳定固定，同时具有高电子转移活性，这是由静电相互作用和疏水力共同驱动的。该表面模拟了天然结合配体，其中粗定向由蛋白质偶极的静电相互作用控制，疏水力有助于形成电子转移复合物。优化后的表面介导的电子转移动力学比其他固体报道的快 100 倍，甚至比烷硫醇自组装单层的动力学还要快。
