Young-sun Lee

One-step pathogen specific DNA extraction from whole blood on a centrifugal microfluidic device

We could, for the first time, demonstrate a fully integrated pathogen specific DNA extraction from whole blood utilizing centrifugal microfluidics on a polymer based CD platform. By combining the TS-LIMBS (target separation and laser-irradiated magnetic bead system) and centrifugal microfluidics using the novel LIFM (the laser irradiated ferrowax microvalves), DNA extraction experiments from whole blood spiked with Hepatitis B virus (HBV) were conducted. The total process was finished within 12 minutes with only one manual step of loading 100 muL of whole blood. Real-time PCR results showed that the concentration of DNA prepared on a CD was as good as that of the samples prepared in conventional bench top method.

Precise temperature control and rapid thermal cycling in a micromachined DNA polymerase chain reaction chip

We have fabricated Si-based micromachined DNA polymerase chain reaction (PCR) chips with different groove depths. The platinum thin-film micro heater and the temperature sensor have been integrated on the chip. The volume of the PCR chamber in the chip is about 3.6 ?l and the chip size is 17 ? 40 mm2. The effects of groove geometry, including width, depth and position, on the thermal characteristics of the PCR chip have been investigated by numerical analysis and experimental measurement. From the results, the power consumption required for the PCR chip is reduced with the increase of groove depth. Compared with results for the case of no groove, the power consumption of the chip with a groove of 280 ?m is reduced by 24.0%, 23.3% and 25.6% with annealing, extension and denaturation, respectively. The heating rate is increased rapidly with the increase of the groove depth. In particular, it is revealed that this effect is predominant for depths in the region above 280 ?m. For a more precise control of chip temperature, the nonlinear feedback proportional-integral control scheme is used. The obtained heating and cooling rates are about 36 ?C s?1 and 22 ?C s?1, respectively. The overshoot and the steady state error are less than 0.7 ?C and ?0.1 ?C, respectively. In the experiment, the effects of the PCR buffer and the bubbles in the chamber on the temperature uniformity have also been studied. From the temperature measurement, it is revealed that the temperature difference between the thin-film sensor (on the lower plate) and the PCR buffer can be neglected if there is no air bubble in the PCR buffer. With such a high performance control scheme, we could implement a remarkable thermal cycling of conducting 30 cycles for 3 min. Finally, the chip PCR of plasmid DNA was successfully performed with no additives using the temperature control system.

One-Step Pathogen Specific DNA Extraction from Whole Blood on a Centrifugal Microfluidic Device

We could, for the first time, demonstrate a fully integrated pathogen specific DNA extraction from whole blood utilizing centrifugal microfluidics on a polymer based CD platform. By combining the TS-LIMBS (target separation and laser-irradiated magnetic bead system) and centrifugal microfluidics using the novel LIFM (the laser irradiated ferrowax microvalves), DNA extraction experiments from whole blood spiked with Hepatitis B virus (HBV) were conducted. The total process was finished within 12 minutes with only one manual step of loading 100 muL of whole blood. Real-time PCR results showed that the concentration of DNA prepared on a CD was as good as that of the samples prepared in conventional bench top method.