Advances in PCR Using Natural Convection
Texas A&M University, US
Keywords: micro fluidics, natural convection, pcr
Abstract:The lack of rapid, affordable, and easy to use medical diagnostic technologies is one of the most critical issues confronting global public health. But a major challenge to the development of instrumentation to meet these needs is the highly inefficient design of conventional PCR thermocycling hardware that is slow, expensive, and consumes considerable electrical power to repeatedly heat and cool the reagent mixture. In this talk I will describe an alternative thermocycling approach that has the potential to addresses these needs by harnessing thermally driven natural convection to perform rapid DNA amplification via the PCR. Here, a buoyancy driven instability is induced within a confined volume of fluid by imposing a spatial temperature gradient. Under the right conditions (fluid properties, chamber geometry, temperature gradient, etc.) a stable circulatory flow pattern can be established that will repeatedly transport PCR reagents through temperature zones associated with each stage of the reaction. The inherently simple design (similar in principle to a lava lamp) and minimal electrical power consumption make this approach well-suited for use in portable applications. I will also describe recent computational and experimental studies in our group that explore the flow fields established within convective thermocycling devices and reveal a rich complexity not found in most steady laminar flows. These complexities arise because, under the thermal conditions associated with PCR, the nature of the buoyancy driven instabilities that initiate and sustain motion make it necessary to operate in a transition regime associated with the onset of convective turbulence. These unique characteristics can be harnessed to guide the design of new devices capable of generating optimal conditions for ultra-rapid PCR.