Electroactive cytochrome c multilayers within a polyelectrolyte assembly
Electroactive cytochrome c multilayers within a polyelectrolyte assembly
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DOI：
10.1002/anie.200352804
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发表时间：
2004-01-01
影响因子：
16.6
通讯作者：
Lisdat, F
中科院分区：
文献类型：
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作者：
Beissenhirtz, MK;Scheller, FW;Lisdat, F
使用生物氧化还原和识别过程构建传感器和生物电子功能[1]是最有前途的。一种合适的组分是细胞色素c，一种已知功能和高稳定性的模型氧化还原蛋白[2-4]。将这种蛋白质排列在电极表面上的许多尝试都是成功的，[5-9]但需要增加功能密度，这可以通过超越单层排列来实现。然而，在较厚的膜或多层膜中，通常只有电极表面附近的蛋白质分子是电活性的。因此，有必要构建稳定的蛋白质多层膜，其中蛋白质可以有效地与电极交换电子，而不需要介体。在这里，这种结构是通过利用逐层吸附技术来实现的，该技术已被证明是构建人工结构的有用工具。[10-15]通过细胞色素c（cyt. c）在阴离子聚苯胺磺酸盐（PASA）和阳离子Cyt溶液中的单层电极。C.单层电极使用连接到金表面和细胞色素的混合烷硫醇（OH-和COOH-封端）构建。C分子吸附到该促进剂层上。这种单层排列已经显示出提供有效的蛋白质-电极通信。[16图1显示了使用PASA作为构建块的所得蛋白质组装体。细胞色素的分步吸附。c和ε通过表面等离子体共振研究验证。该技术也被用来确定自组织过程的最佳工作条件。使用循环伏安法的电化学研究表明，在电极上的蛋白质负载的增加对应于在电极可寻址的细胞色素的量的增加。c分子。重复孵育步骤导致伏安峰面积增加，从而可以定量电活性蛋白质的量（图2）。包含多达15个蛋白质层的多层膜显示出向电极的准可逆电子转移，具有高重现性。对照实验中，无论是PASA或细胞色素。用缓冲液代替C溶液，仅显示出单层电极的响应，这表明两种化合物对于成功形成多层蛋白质组装体都是必需的。蛋白质的形式电位测定为1.15 × 1.7mV（相对于Ag/AgCl/1 m KCl），因此在cyt测定值的实验误差范围内。c单层电极（± 19 mV）。峰宽增加，
The use of biological redox and recognition processes for the construction of sensors and bioelectronic functionalities [1] is most promising. One suitable component is cytochrome c, a model redox protein [2-4] of known function and high stability. Numerous attempts to arrange this protein on electrode surfaces have been successful,[5–9] but there is a need to increase the functional density and this can be achieved by going beyond the monolayer arrangement. However, in thicker films or multilayers, generally only protein molecules near the electrode surface are electroactive. Therefore it is necessary to construct stable films of protein multilayers in which the proteins can effectively exchange electrons with the electrode without the need of a mediator. Herein this construction is achieved by making use of the layer-by-layer adsorption technique which has been shown to be a useful tool in building up artificial architectures.[10–15] Fully electroactive multilayer assemblies were built up by alternating incubation steps of a cytochrome c (cyt. c) monolayer electrode in solutions of anionic polyaniline sulfonate (PASA) and cationic cyt. c. The monolayer electrode was constructed using mixed alkanethiols (OH-and COOH-terminated) attached to a gold surface and cyt. c molecules which were adsorbed to this promoter layer. This monolayer arrangement has been shown to provide an efficient protein–electrode communication.[16, 17] Figure 1 shows the resulting protein assembly using PASA as a building block. The stepwise adsorption of cyt. c and polyelectrolyte was verified by surface plasmon resonance investigations. The technique was also used to determine optimal working conditions for the self-organizing process. Electrochemical studies using cyclic voltammetry showed that the increase in protein loading on the electrode corresponds to an increase in the electrode-addressable amount of cyt. c molecules. Repeated incubation steps resulted in an enhancement of the voltammetric peak area allowing for a quantification of the electroactive protein amount (Figure 2). Multilayers containing up to 15 protein layers showed a quasi-reversible electron transfer to the electrode, with a high reproducibility. Control experiments in which either the PASA or the cyt. c solution was replaced by buffer showed only the response of a monolayer electrode, which demonstrates that both compounds are necessary for a successful formation of the multilayer protein assembly. The formal potential of the protein was determined to be À15 Æ 7 mV (versus Ag/AgCl/1m KCl) and thus is within the experimental error of the value found for cyt. c monolayer electrodes (À19 Æ 5 mV). An increase in the peak width at