No abstract

Microwave energy has been used to rapidly heat food and drinks for decades, in addition to assisting other chemical reactions. However, only recently has microwave energy been applied in microfluidic systems to heat solution in reaction chambers, in particular, the polymerase chain reaction (PCR). One of the difficulties in developing microwave-mediated heating on a microchip is the construction of the appropriate architecture for delivery of the energy to specific micro-areas on the microchip. This work employs commercially-available microwave components commonly used in the wireless communications industry to generate a microwave signal, and a microstrip transmission line to deliver the energy to a 1 μL reaction chamber fabricated in plastic microdevices. A model was developed to create transmission lines that would optimally transmit energy to the reaction chamber at a given frequency, minimizing energy usage while focusing microwave delivery to the target chamber. Two different temperature control methods were demonstrated, varying microwave power or frequency. This system was used to amplify a fragment of the lambda-phage genome, thereby demonstrating its potential for integration into a portable PCR system.

No abstract

No abstract

A significant challenge in the fabrication of thin-film (<1 µm) Au MEMS devices is maintaining planarity after removal of the sacrificial layer. Out-of-plane deformations are driven by residual stress gradients in the Au films. It was found that the baking time and temperature of the sacrificial photoresist layer, as well as the thermal history once the Au was deposited, combined to determine the stress gradient within the Au film. In this technical note we provide the complete details of the optimized procedures to fabricate planar thin-film Au devices with unattached ends that are characterized by low residual stresses.