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

疫情凸显了社会和医疗保健方面许多未得到满足或部分满足的需求。有效、简单、准确及敏感的生物传感能力的可用性已成为应对大流行及随后的医疗保健挑战的战略的关键部分。使用电化学检测和测量开发的生物传感器形成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，以便在复杂介质中特异性地检测感兴趣的分析物。制备这些传感器用于商业化的挑战很多，但不可避免地涉及电极表面的改性和稳定性、表面改性的质量和底层基底的特性。在测量条件下（例如，在缓冲器中或原位），尽管仅存在少数技术，但需要更多的技术。在缓冲区中进行表面分析是困难的，需要许多互补的方法来获得无偏差的结果。当在缓冲器中时，在结合目标之前或之后，洞察基于表面的探针或传感器换能器的条件对于针对特定分析需要定制设计和表面工程是重要的。开发表征真实的传感器的新的原位表面分析方法将推进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改性电极表面，并解决了上述许多挑战。所用的衬底是单晶珠电极，其包含完整的立体三角形，该三角形提供了对构成底层衬底的原子的所有形式的排列的访问。该电极提供了对通常在多晶金基底上制备的传感器的独特见解（例如，具有随机变化的表面结构，如由高能晶界分隔的晶粒）。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。吸附分子的分布和组织将通过发展单分子光学方法来探索。这将使研究的局部环境的吸附，单分子识别的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。这些结果将被用于工程表面，使新的检测方式，这将结合联合收割机电化学和荧光方法的双重检测方案。

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.