A 16 x 16 CMOS Capacitive Biosensor Array Towards Detection of Single Bacterial Cell
(2015) IEEE Transactions on Biomedical Circuits and Systems — (2015)
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- Abstract
- We present a 16 x 16 CMOS biosensor array aiming at impedance detection of whole-cell bacteria. Each 14 µm x 16 µm pixel comprises high-sensitive passivated microelectrodes connected to an innovative readout interface based on charge sharing principle for capacitive-to-voltage conversion and subthreshold gain stage to boost the sensitivity; Fabricated in a 0.25 µm CMOS process, the capacitive array was experimentally shown to perform accurate dielectric measurements of the elctrolyte up to electrical conductivities of 0.05 S/m, with maximal sensitivity of 55 mV/fF and signal-to-noise ratio (SNR) of 37 dB. As biosensing proof of concept, real-time detection of Staphylococcus epidermidis binding events was experimentally demonstrated and provides detection limit of ca. 7 bacteria per pixel and sensitivity of 2.18 mV per bacterial cell. Models and simulations show good matching with experimental results and provide a comprehensive analysis of the sensor and circuit system. Advantages, challenges and limits of the proposed capacitive biosensor array are finally described with regards to literature. With its small area and low power consumption, the present capacitive array is particularly suitable for portable point-of-care (PoC) diagnosis tools and lab-on-chip (LoC) systems.
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Citations
Couniot, N., Francis, L., & Flandre, D. (2015). A 16 x 16 CMOS Capacitive Biosensor Array Towards Detection of Single Bacterial Cell. IEEE Transactions on Biomedical Circuits and Systems. Accepted/in-press. https://doi.org/10.1109/TBCAS.2015.2416372 (Original work published 2015)