Unmet NeedMaintaining levels of crop production has become increasingly critical amidst growing populations and other emerging challenges for the $300 billion global crop market.
Traditional crossbreeding of plants for desirable phenotypic traits is being improved by genetic marker assisted selection (MAS), where known genetic markers associated with traits of interest (i.e., durability, productivity, disease resistance, etc.) are selected increasing the efficiency and precision of conventional plant breeding. At commercial agricultural scales, MAS techniques require assaying a large number of markers from numerous plant samples, involve robotic handling of samples, utilize ‘greater than microliter’ quantities of precious samples, and are quite costly and relatively slow.
Compared to industrial-sized robotic systems, droplet microfluidic devices are capable of processing high-throughput screening assays using compact, inexpensive setups while limiting valuable sample consumption to nanoliter volumes. Even so, existing droplet microfluidic devices have yet to achieve highly multiplexed genetic detection assays in a continuous-flow and high-throughput manner, thus rendering them impractical for many commercial-scale applications.
Technology OverviewJohns Hopkins inventors have developed a high-throughput platform for performing MAS genetic-enhanced breeding processes within a droplet microfluidic device in a continuous-flow and high-throughput assay. The overall platform includes: a droplet microfluidic device, multi-temperature incubation zones and an optical detection apparatus.
Specifically, the platform is capable of the following operations: 1) injection of samples into nanoliter droplets via programmable microvalves, 2) delivery of genetic marker probes into reaction droplets, 3) mixing of droplets, 4) incubation of mixed droplets by transporting them through micro-channels heated at pre-programmed temperatures required for the specific genetic assay, and 5) detection of fluorescence signals corresponding to specific genetic markers in droplets.
Custom software control, multi-temperature zones and optical detection apparatus offers the flexibility to perform different types of assays (e.g., PCR or Invader). While the intended application of this platform is genetic amplification and detection assays, it can be used for other applications that require multi-component assays to be performed within a droplet microfluidic device.
Stage of DevelopmentA semi-automatic working prototype with a single main channel is available. In the future, this platform will be fully automated with improved multiplexing capability and a linear CCD detector so reactions in multiple channels can be incubated and processed in parallel.
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