CMOS Conductometric System for Growth Monitoring and Sensing of Bacteria

• Published in: IEEE transactions on biomedical circuits and systems Vol. 5; no. 3; pp. 223 - 230
• Main Authors: Lei Yao, Lamarche, P, Tawil, N, Khan, R, Aliakbar, A M, Hassan, M H, Chodavarapu, V P, Mandeville, R
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-06-2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bacteria; bacteria sensing; Bacterial growth monitoring; bacteriophage; biosensor; CMOS integrated circuits; complementary metal-oxide semiconductor (CMOS); conductometric sensor; E coli; electrochemical sensor; Electrodes; Escherichia coli; escherichia coli (E.coli); Immune system; Microorganisms; Monitoring; MOS devices; Sensors
• ISSN: 1932-4545; 1940-9990
• DOI: 10.1109/TBCAS.2010.2089794

We present the design and implementation of a prototype complementary metal-oxide semiconductor (CMOS) conductometric integrated circuit (IC) for colony growth monitoring and specific sensing of Escherichia coli (E. coli) bacteria. The detection of E. coli is done by employing T4 bacteriophages as receptor organisms. The conductometric system operates by measuring the resistance of the test sample between the electrodes of a two-electrode electrochemical system (reference electrode and working electrode). The CMOS IC is fabricated in a TSMC 0.35-μm process and uses a current-to-frequency (I to F) conversion circuit to convert the test sample resistance into a digital output modulated in frequency. Pulsewidth control (one-shot circuit) is implemented on-chip to control the pulsewidth of the output digital signal. The novelty in the current work lies in the ability of the CMOS sensor system to monitor very low initial concentrations of bacteria (4×10 2 to 4×10 4 colony forming unit (CFU)/mL). The CMOS system is also used to record the interaction between E. coli and its specific receptor T4 bacteriophage. The prototype CMOS IC consumes an average power of 1.85 mW with a 3.3-V dc power supply.