[Micromachines] A Programmable Digital Microfluidic Assay for the Simultaneous Detection of Multiple
The rapid emergence of antimicrobial resistant bacteria requires the development of new diagnostic tests. Nucleic acid-based assays determine antimicrobial susceptibility by detecting genes that encode for the resistance. In this study, we demonstrate rapid and simultaneous detection of three genes that confer resistance in bacteria to extended spectrum β-lactam and carbapenem antibiotics; CTX-M-15, KPC and NDM-1. The assay uses isothermal DNA amplification (recombinase polymerase amplification, RPA) implemented on a programmable digital microfluidics (DMF) platform. Automated dispensing protocols are used to simultaneously manipulate 45 droplets of nL volume containing sample DNA, reagents, and controls. The droplets are processed and mixed under electronic control on the DMF devices with positive amplification measured by fluorescence. The assay on these devices is significantly improved with a Time to Positivity (TTP) half that of the benchtop assay.
Sumit Kalsi 1, Samuel L. Sellars 1, Carrie Turner 2, J. Mark Sutton 2 and Hywel Morgan 1,* 1 Electronics and Computer Science, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK 2 National Infections Service, Public Health England, Porton Down, Salisbury SP4 0JG, UK * Author to whom correspondence should be addressed.