Calibration-Free CMOS Capacitive Sensor for Life Science Applications
In: IEEE Transactions on Instrumentation and Measurement, Jg. 70 (2021), S. 1-12
Online
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Zugriff:
CMOS capacitive sensors reported for high-accuracy cellular molecular measurements typically suffer from significant parasitic capacitance changes caused by remnants and sediments during the experiment with several biological and chemical reactions. In this article, we propose a novel calibration-free capacitive sensing system that addresses this problem. The proposed CMOS capacitive sensor includes interdigitated electrodes (IDEs), a capacitance-to-current converter with a wide input dynamic range (IDR), a variable reference capacitor, and an oscillator-based analog-to-digital converter (ADC) which has been fabricated using $0.35~\mu \text{m}$ AMS CMOS process. Sweeping the value of the variable reference capacitor from 0.1 fF up to 1.27 pF with a step of 10 fF and repeating the sweep each second during the experiment allows the creation of time-resolved three-dimensional (3-D) fingerprints for the measurement of capacitance variations of the sample-electrode interface resulted from both the target material as well as non-target parasitic capacitances. We have tested the sensor using three different chemical solvents. The four different categories of curves that constitute the fingerprints of the chemicals showed a match with the post-layout simulation results. Capacitance change in the range of 0.416 fF up–1.27 pF can practically be monitored. The electrode area of 110 by $220~\mu \text{m}$ and the micrometer chamber size allows for placing tiny droplets of a few microliters. The generated fingerprint is valid for the chemicals with a conductivity of up to 5 mS/cm.
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Calibration-Free CMOS Capacitive Sensor for Life Science Applications
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Autor/in / Beteiligte Person: | Bozkurt, Ayhan ; Hamed Osouli Tabrizi ; Ghafar-Zadeh, Ebrahim ; Farhanieh, Omid ; Magierowski, Sebastian ; Forouhi, Saghi |
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Zeitschrift: | IEEE Transactions on Instrumentation and Measurement, Jg. 70 (2021), S. 1-12 |
Veröffentlichung: | Institute of Electrical and Electronics Engineers (IEEE), 2021 |
Medientyp: | unknown |
ISSN: | 1557-9662 (print) ; 0018-9456 (print) |
DOI: | 10.1109/tim.2021.3116294 |
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