Issue 14, 2015

Rapid and sensitive detection of antibiotic resistance on a programmable digital microfluidic platform

Abstract

The widespread dissemination of CTX-M extended spectrum β-lactamases among Escherichia coli bacteria, both in nosocomial and community environments, is a challenge for diagnostic bacteriology laboratories. We describe a rapid and sensitive detection system for analysis of DNA containing the blaCTX-M-15 gene using isothermal DNA amplification by recombinase polymerase amplification (RPA) on a digital microfluidic platform; active matrix electrowetting-on-dielectric (AM-EWOD). The devices have 16 800 electrodes that can be independently controlled to perform multiple and simultaneous droplet operations. The device includes an in-built impedance sensor for real time droplet position and size detection, an on-chip thermistor for temperature sensing and an integrated heater for regulating the droplet temperature. Automatic dispensing of droplets (45 nL) from reservoir electrodes is demonstrated with a coefficient of variation (CV) in volume of approximately 2%. The RPA reaction is monitored in real-time using exonuclease fluorescent probes. Continuous mixing of droplets during DNA amplification significantly improves target DNA detection by at least 100 times compared to a benchtop assay, enabling the detection of target DNA over four-order-of-magnitude with a limit of detection of a single copy within ~15 minutes.

Graphical abstract: Rapid and sensitive detection of antibiotic resistance on a programmable digital microfluidic platform

Supplementary files

Article information

Article type
Paper
Submitted
22 Apr 2015
Accepted
10 Jun 2015
First published
18 Jun 2015

Lab Chip, 2015,15, 3065-3075

Rapid and sensitive detection of antibiotic resistance on a programmable digital microfluidic platform

S. Kalsi, M. Valiadi, M. Tsaloglou, L. Parry-Jones, A. Jacobs, R. Watson, C. Turner, R. Amos, B. Hadwen, J. Buse, C. Brown, M. Sutton and H. Morgan, Lab Chip, 2015, 15, 3065 DOI: 10.1039/C5LC00462D

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