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

Lab Chip. 2015 Jul 21;15(14):3065-75. doi: 10.1039/c5lc00462d.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA, Bacterial / analysis*
  • DNA, Bacterial / genetics*
  • Drug Resistance, Microbial / genetics*
  • Electrodes
  • Escherichia coli / drug effects*
  • Escherichia coli / genetics*
  • Fluorescence
  • Microfluidic Analytical Techniques* / instrumentation
  • Nucleic Acid Amplification Techniques / instrumentation
  • Particle Size
  • Surface Properties
  • Temperature
  • Time Factors


  • DNA, Bacterial