Impact of Self-Assembled Monolayer Design and Electrochemical Factors on Impedance-Based Biosensing
Impact of Self-Assembled Monolayer Design and Electrochemical Factors on Impedance-Based Biosensing
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DOI：
10.3390/s20082246
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发表时间：
2020-04-01
期刊：
影响因子：
3.9
通讯作者：
Kim, Steve S.
中科院分区：
文献类型：
--
作者：
Brothers, Michael C.;Moore, David;Kim, Steve S.
蛋白质的实时检测，特别是在可穿戴设备中，仍然是一个巨大的挑战，因为需要将结合事件转换为与所选分析仪器兼容的可测量信号。阻抗谱可通过测量静电相互作用或电子转移反应实现实时检测，同时还可实现小型化，以便集成到可穿戴外形中。为了创建一种更可靠的方法来优化基于阻抗的传感器，需要进行额外的基础研究，探索影响这些传感器的设计和实现的组件。这项研究通过结合光学和电化学表征来验证基于阻抗的传感器性能作为(1)生物识别元件密度、(2)自组装单分子层链长、(3)自组装单分子层电荷密度、(4)电化学传感机制和(5)氧化还原报告选择的函数来解决这些问题的子集。使用现有的溶菌酶适配子和溶菌酶分析物组合，我们展示了一些设计标准，以促进蛋白质传感的最先进水平。对于这个模型系统，我们展示了以下内容：首先，密度更高的自组装单分子膜产生了显著改善的传感结果。第二，自组装单分子膜组成，包括厚度和电荷密度，改变了观察到的峰位置和峰电流。第三，单频测量虽然信息量较少，但可以优化以取代多频测量，在某些情况下(例如使用两性离子自组装单分子膜)是首选的。最后，应进一步探索传统上不用于阻抗传感的各种氧化还原记录器。总而言之，这些成果可以帮助限制与设备开发相关的瓶颈，从而实现下一代基于阻抗的生物传感，并为特定应用定制传感器设计。
Real-time sensing of proteins, especially in wearable devices, remains a substantial challenge due to the need to convert a binding event into a measurable signal that is compatible with the chosen analytical instrumentation. Impedance spectroscopy enables real-time detection via either measuring electrostatic interactions or electron transfer reactions while simultaneously being amenable to miniaturization for integration into wearable form-factors. To create a more robust methodology for optimizing impedance-based sensors, additional fundamental studies exploring components influencing the design and implementation of these sensors are needed. This investigation addresses a sub-set of these issues by combining optical and electrochemical characterization to validate impedance-based sensor performance as a function of (1) biorecognition element density, (2) self-assembled monolayer chain length, (3) self-assembled monolayer charge density, (4) the electrochemical sensing mechanism and (5) the redox reporter selection. Using a pre-existing lysozyme aptamer and lysozyme analyte combination, we demonstrate a number of design criteria to advance the state-of-the-art in protein sensing. For this model system we demonstrated the following: First, denser self-assembled monolayers yielded substantially improved sensing results. Second, self-assembled monolayer composition, including both thickness and charge density, changed the observed peak position and peak current. Third, single frequency measurements, while less informative, can be optimized to replace multi-frequency measurements and in some cases (such as that with zwitterionic self-assembled monolayers) are preferred. Finally, various redox reporters traditionally not used in impedance sensing should be further explored. Collectively, these results can help limit bottlenecks associated with device development, enabling realization of next-generation impedance-based biosensing with customize sensor design for the specific application.