Abstract

A Microfluidic Solution to Rapid, Simple, Bedside Blood Testing

James Landers, Commonwealth Professor, University of Virginia

In 2006, we demonstrated that microfluidic technology could provide a ‘lab-on-a-chip’ solution for real-world genetic analysis.  Sample-in/answer-out functionality was shown for the detection of bacteria in mouse blood and in a human nasal swab, with a sub-30 minute analytical time for DNA extraction, amplification, electrophoretic separation and detection.  We extrapolated these technology developments to the analysis of short tandem repeats (STR) in human DNA; these clinically-insignificant (presumably) tetranucleotide sequences function effectively for statistically-relevant matching in human identification. Our efforts led to the development of a commercializable system designed for implementation in crime labs for STR profiling convicted felons or, in some states, profiling arrestees in booking stations. An intricate but functional microfluidic architecture allowed sample-to-profile to be achieved from a cheek swab in less than 80 minutes, using nanoliter flow control, infrared thermocycling and rapid electrophoretic separation of DNA with 5-color fluorescence detection. We have since demonstrated the fabrication of hybrid microdevices composed of inexpensive polymeric materials, many of these commercial-off-the-shelf.  We have designed, built and functionalized fully-integrated DNA analysis chemistry/microfluidics on a rotationally-driven system the size of a compact disc. With this system, DNA can be extracted from a swab, PCR amplified to generate an abundance of DNA fragments of the STR loci, followed by resolution of those fragments in a separation in a 4 cm Leff channel that is complete in <300 sec with a 2-base resolution.  The processes that allow for swab in–profile out microfluidics are carried out on an instrument that can be carried in one hand and weighs ~14 lbs, ultimately allowing for facile rapid human identification/screening in the field.