In-situ study of electrochemical interfaces modified by adsorbed organic molecules; characterizing heterogeneous adsorbate coverage with application to biosensors

被吸附的有机分子修饰的电化学表面的原位表征是使用许多不同的方法完成的。我们开发了一种结合荧光显微镜和电化学的独特方法。这种方法被证明对表征表面涂层的非均质性很有用，从而能够更详细地研究这些表面，从而提出了一些重要的问题。 先进生物传感器的创建依赖于表面的修饰，以提供能够检测溶液中分析物的功能界面。根据传感器表面吸附分子的取向，已经形成了许多有趣的模体。这些分子(如DNA)可以包括氧化还原活性部分，这些部分提供简单的电化学信号(电流)，可用于信号转导。在某些情况下，结合后电流会降低，这在缓冲液和复杂介质中已经观察到。最近用我们的原位荧光显微镜方法对DNA修饰的金表面的研究表明，按照现有的文献方法创建的这些表面并不是均匀的，实际上是非常不均匀的。这一令人惊讶的结果导致了一些问题，本研究提案旨在回答这些问题。这些曲面是简化卡通中呈现的吗？我们的方法是否突出了这些不完美之处，这是目前的分析方法很难确定的？我们能否改变用于制造这些传感器的程序，以消除或最小化这些不受欢迎的功能？与欧洲的两个电化学研究小组合作，我们将扩大我们将组装到电极表面的分子类型(适配子、多肽、DNA)。我们的目标是了解这些传感器表面，并使用我们独特的现场表征工具，确定导致这些异质区域的系统特征，并评估对传感器响应的影响。我们还打算使用这种方法继续我们的研究，以创建一个支撑在电极上的生物膜模型，并调查控制电化学解吸分子运动的力的性质。

In-situ characterization of electrochemical surfaces modified by adsorbed organic molecules is accomplished using a number of different approaches. We have developed a unique method that combines fluorescence microscopy and electrochemistry. This method is proving useful for characterizing the heterogeneity of surface coating, enabling the study of these surfaces with more detail thereby raising some important questions. The creation of advanced biosensors relies on the modification of surfaces to provide a functional interface that can sense the analyte in solution. A number of interesting motifs have been developed that rely upon the orientation of the adsorbed molecules on the sensor surface. These molecules (eg DNA) can include redox active moieties that provide a simple electrochemical signal (current) that can be used for signal transduction. In some cases, the current decreases upon binding, and this has been observed in buffers and complex media. Recent studies of the DNA modified gold surface with our in-situ fluorescence microscopic method has revealed that these surface, created following current literature procedures, are not homogeneous and are, in fact quite heterogeneous. This surprising result has resulted in a number of questions that this research proposal aims to answer. Are these surfaces as presented in simplified cartoons? Does our method highlight these imperfections, something that is hard to determine using the current analytical methods? Can we change the procedures used to make these sensors to eliminate or minimize these undesirable features? In collaboration with two electrochemical research groups in Europe, we will expand the types of molecules that we will assemble onto the electrode surface (aptamers, peptides, DNA). We aim to understand these sensor surfaces and with our unique in-situ characterization tool, determine the characteristics of the system that contribute to these heterogeneous regions, and assess the impact on sensor response. We also intend to use this method to continue our studies into creating a model of a biomembrane supported on an electrode, and to investigate the nature of the forces that govern the movement of molecules that are electrochemically desorbed.