Glass-Based Continuous-Flow PCR Chip With a Portable Control System for DNA Amplification

Abstract

A glass-based continuous-flow polymerase chain reaction (PCR) chip has been designed and fabricated. The device consists of a glass microfluidic channel, three NiCr heaters, and three Ni thermometers on the silicon substrate. An intelligent temperature-control circuit system has been designed to achieve desirable temperature control (95, 72, and 55 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}{\rm C}$</tex></formula> ) at the three temperature zones of the PCR chip. Simulation underneath the microfluidic channel using the finite element method shows that the temperature distribution through the three temperature zones are relatively uniform. A mixture of DNA samples for PCR was allowed to flow through the microfluidic channel under different flow rates. The amplified sample of the target DNA obtained from the PCR chip was then separated by electrophoresis and was analyzed using an ultraviolet analyzer. The result indicates that DNA amplification can be achieved and that its amplification factor depends greatly on the injection rate of the sample. The optimum sample-flow rate is 0.6 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu{\rm l}/{\rm min}$</tex></formula> .