Highly Sensitive Readout Interface for Real-Time Differential Precision Measurements with Impedance Biosensors

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Field deployment is critical to developing numerous sensitive impedance transducers. Precise, cost-effective, and real-time readout units are being sought to interface these sensitive impedance transducers for various clinical or environmental applications. This paper presents a general readout method with a detailed design procedure for interfacing impedance transducers that generate small fractional changes in the impedance characteristics after detection. The emphasis of the design is obtaining a target response resolution considering the accuracy in real-time. An entire readout unit with amplification/filtering and real-time data acquisition and processing using a single microcontroller is proposed. Most important design parameters, such as the signal-to-noise ratio (SNR), common-mode-to-differential conversion, digitization configuration/speed, and the data processing method are discussed here. The studied process can be used as a general guideline to design custom readout units to interface with various developed transducers in the laboratory and verify the performance for field deployment and commercialization. A single frequency readout unit with a target 8-bit resolution to interface differentially placed transducers (e.g., bridge configuration) is designed and implemented. A single MCU is programmed for real-time data acquisition and sine fitting. The 8-bit resolution is achieved even at low SNR levels of roughly 7 dB by setting the component values and fitting algorithm parameters with the given methods.

real-time, impedance biosensor, low-cost, precision, sensitive, readout, interface, SPECTROSCOPY, ALGORITHM, AMPLITUDE, Chemistry, Analytical, Nanoscience & Nanotechnology, Instruments & Instrumentation
Neshani, S., Momeni, K., Chen, D. J., & Neihart, N. M. (2023). Highly Sensitive Readout Interface for Real-Time Differential Precision Measurements with Impedance Biosensors. In Biosensors (Vol. 13, Issue 1, p. 77). MDPI AG. https://doi.org/10.3390/bios13010077