A Si-based miniaturized reactor has been developed for efficient DNA amplification by polymerase chain reaction (PCR). The 8 μ1 reaction chamber is formed by KOH etching of a silicon substrate and is sealed with Corning 7740 glass utilizing an improved anodic bonding process. The device has platinum temperature sensors and heaters integrated on top of a thin silicon membrane capping the reaction chamber for real-time temperature sensing and control. The reaction temperature of the device is digitally controlled to achieve an accuracy of [superscrpt +]_-O.O5℃, heating and cooling rates of 5.7℃/s and 3.3℃/s respectively. Power consumption of the reactor is small, only 1.6 W is sufficient to heat up the reaction chamber to 95℃, the denaturation step of PCR....[ Read more ]

A Si-based miniaturized reactor has been developed for efficient DNA amplification by polymerase chain reaction (PCR). The 8 μ1 reaction chamber is formed by KOH etching of a silicon substrate and is sealed with Corning 7740 glass utilizing an improved anodic bonding process. The device has platinum temperature sensors and heaters integrated on top of a thin silicon membrane capping the reaction chamber for real-time temperature sensing and control. The reaction temperature of the device is digitally controlled to achieve an accuracy of [superscrpt +]_-O.O5℃, heating and cooling rates of 5.7℃/s and 3.3℃/s respectively. Power consumption of the reactor is small, only 1.6 W is sufficient to heat up the reaction chamber to 95℃, the denaturation step of PCR.

In addition to good thermal control, the reaction chamber surface must be appropriately treated or passivated to achieve high amplification efficiency. In this study, the device demonstrates DNA amplification efficiency as high as that in the conventional thermal cycler, with either chlorotrimethylsilane (CTMS) treatment followed by polyadenylic acid incubation or silicon oxide coating on the silicon reaction chamber surface. Moreover, the amount of MgCl₂ in the PCR reaction mixture has to be optimized in chip setting, which can be very different from that in the conventional setting. For all four Traditional Chinese Medicine (TCM) genes studied, the amplification efficiency in the chip reactor is comparable to that in the conventional thermal cycler.

This PCR module will eventually be integrated with other "Biochip" components such as sample preparation, product separation as well as detection, and hybridization chip to realize a portable, battery-operated and comprehensive DNA analyzer for use in identification of authentic TCM and discovery of potential novel drugs derived from TCM.