Understanding and controlling complex modified electrochemical interfaces using novel measurements and model systems

大流行凸显了社会和卫生保健领域许多未得到满足或部分得到满足的需求。提供有效、简单、准确和灵敏的生物感应能力是应对这一流行病及其带来的未来保健挑战和应对未来挑战战略的一个关键部分。利用电化学检测和测量技术开发的生物传感器是便携式传感器生态系统的重要组成部分。它们需要对电极表面进行复杂的修饰，以便在复杂的介质中特异性地检测感兴趣的分析物。在为商业化准备这些传感器的过程中存在许多挑战，但不可避免地涉及电极表面的修饰和稳定性，表面修饰的质量以及底层衬底的特性。在测量条件下（例如，在缓冲液或原位），了解分子水平上的界面特性是必要的，尽管只有少数技术存在，但需要更多的技术。表面分析，而在缓冲是困难的，需要许多互补的方法来实现无偏的结果。深入了解基于表面的探头或传感器传感器在缓冲、绑定目标之前或之后的情况，对于定制设计和表面工程以满足特定分析需求非常重要。开发新的原位表面分析方法来表征真实传感器将促进传感器的发展和商业化。该研究计划使用我们独特的原位荧光显微镜光谱电化学方法来研究修饰的电极表面，并解决上述许多挑战。所使用的衬底是一个单晶珠电极，包含完整的立体三角形，可以访问构成衬底的原子的所有形式的排列。该电极为通常在多晶金衬底上制备的传感器提供了独特的见解（例如，具有随机变化的表面结构，如由高能晶界分隔的颗粒）。了解这些结构特征的作用已被证明是提高传感器稳定性和传感性能的关键。通过发展单分子光学方法来探索吸附分子的分布和组织。这将有助于研究吸附物的局部环境、单分子识别动力学和分析物结合效率的分布。先进的原位表面表征将指导制备传感器表面的新方法，实现对吸附物密度、局部环境和分布的控制。这将提高传感器的稳定性和性能。这些结果将用于设计表面，以实现新的检测方式，将电化学和荧光方法结合在双重检测方案中。

The pandemic has highlighted the many unmet, or partially met, needs in society and in healthcare. The availability of effective, simple, accurate and sensitive bio-sensing capacities was realized as a critical part of the strategy for dealing with the pandemic and ensuing healthcare challenge going forward and for future challenges. Biosensors developed using electrochemical detection and measurement form an important part of the portable sensor ecosystem. They require sophisticated modification of the electrode surface so as to specifically detect the analyte of interest in complex media. Challenges in preparing these sensors for commercialization are many, but inevitably involve the modification and stability of the electrode surface, the quality of the surface modification and the characteristics of the underlying substrate. Understanding the interfacial characteristics at the molecular level while under measurement conditions (e.g., in buffer or in-situ) is required, though only a few techniques exist and more are needed. Surface analysis while in buffer is difficult and requires many complimentary approaches to achieve an unbiased result. Insight into the conditions of the surface-based probe or sensor transducer when in buffer, before or after binding the target is important for tailoring the design and surface engineering for the specific analytical need. Developing new in-situ surface analysis methods for characterizing real sensors will advance sensor development and commercialization. This research programme uses our unique in-situ fluorescence microscopy spectroelectrochemical methodology to study modified electrode surfaces and addresses many of the challenges above. The substrate used is a single crystal bead electrode that contains the complete stereographic triangle which provides access to all forms of the arrangement of the atoms that make up the underlying substrate. This electrode provides a unique insight into sensors that are typically prepared on poly-crystalline gold substrates (e.g., have a random variety of surface structures like grains separated by high energy grain boundaries). Understanding the role of these structural features has proven critical for improving sensor stability and sensing performance. The distribution and organization of the adsorbed molecules will be explored by developing single molecule optical methods. This will enable study of the local environment of the adsorbate, kinetics of single molecule recognition and the distribution of analyte binding efficiency. Advanced in-situ surface characterization will direct new methods for preparing the sensor surface achieving control over density, local environment and distribution of the adsorbates. This will improve sensor stability and performance. These results will be used to engineer surfaces to enable new detection modalities which will combine electrochemical and fluorescence methods in a dual detection scheme.