文章基本信息

标题：AC and DC Differential Bridge Structure Suitable for Electrochemical Interfacial Capacitance Biosensing Applications
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作者：Sara Neshani ; Charles K. A. Nyamekye ; Scott Melvin 等
期刊名称：Biosensors
电子版ISSN：2079-6374
出版年度：2020
卷号：10
期号：3
页码：28-50
DOI：10.3390/bios10030028
出版社：MDPI Publishing
摘要：This paper presents a capacitive differential bridge structure with both AC and DC excitation and balancing capability for low cost electrode-solution interfacial capacitance biosensing applications. The proposed series RC balancing structure offers higher sensitivity, lower susceptibility to common-mode interferences, and drift control. To evaluate the bridge performance in practice, possible effects of initial bridge imbalance due to component mismatches are investigated considering the required resolution of the balancing networks, sensitivity, and linearity. This evaluation is also a guideline to designing the balancing networks, balancing algorithm and the proceeding readout interface circuitry. The proposed series RC bridge structure is implemented along with a custom single frequency real-time amplification/filtering readout board with real-time data acquisition and sine fitting. The main specifications for the implemented structure are 8-bit detection resolution if the total expected fractional capacitance change at the interface is roughly 1%. The characterization and measurement results show the effectiveness of the proposed structure in achieving the design target. The implemented structure successfully achieves distinct detection levels for tiny total capacitance change at the electrode-solution interface, utilizing Microcystin-(Leucine-Arginine) toxin dilutions as a proof of concept.
关键词：biosensor; electrochemical capacitive bridge; sensitivity; linearity; low-cost; AC/DC excitation; balancing; field deployable; drift; real-time biosensor ; electrochemical capacitive bridge ; sensitivity ; linearity ; low-cost ; AC/DC excitation ; balancing ; field deployable ; drift ; real-time