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

这场大流行突显了社会和医疗保健中许多未得到满足或部分得到满足的需求。提供有效、简单、准确和敏感的生物传感能力是应对这一流行病和随之而来的卫生保健挑战以及未来挑战的战略的关键部分。利用电化学检测和测量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专门检测感兴趣的分析物。为商业化准备这些传感器的挑战很多，但不可避免地涉及电极表面的修饰和稳定性、表面修饰的质量和底层衬底的特性。在测量条件下(例如，在缓冲液中或在现场)，需要在分子水平上了解界面特征，尽管只有几种技术存在，还需要更多技术。在缓冲区中进行表面分析是困难的，需要许多互补的方法才能获得公正的结果。深入了解表面探头或传感器换能器在缓冲液中、结合靶材之前或之后的情况，对于为特定分析需求量身定做设计和表面工程非常重要。开发用于表征真实传感器的新的原位表面分析方法将推动传感器的开发和商业化。这项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电极表面，并解决了上述许多挑战。所使用的衬底是单晶珠电极，它包含完整的立体三角形，可以访问组成底层衬底的原子的所有形式的排列。该电极提供了对通常在多晶金衬底上制备的传感器的独特洞察(例如，具有随机变化的表面结构，如被高能晶界隔开的颗粒)。事实证明，了解这些结构特征的作用对于提高传感器的稳定性和传感性能至关重要。将通过发展单分子光学方法来探索吸附分子的分布和组织。这将使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成为可能。先进的原位表面表征将指导制备传感器表面的新方法，实现对密度、局部环境和吸附物分布的控制。这将提高传感器的稳定性和性能。这些结果将被用来设计表面，以实现新的检测模式，这种模式将在双重检测方案中结合电化学和荧光方法。

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.