Hybrid microsystem with functionalized silicon substrate and PDMS sample operating microchannel: A reconfigurable microfluidics scheme

Abstract

A hybrid microsystem with separately functioned temperature controlling substrate and sample operating fluidic microchannel was developed to demonstrate a reconfigurable microfluidics scheme. The temperature controlling substrate integrated a micro heater and a temperature sensor by using traditional silicon-based micromechanical system (MEMS) technique, which guaranteed high performance and robust reliability for repeatable usage. The sample operating fluidic microchannel was prepared by poly-(dimethylsiloxane) (PDMS) based soft lithography technique, which made it cheap enough for disposable applications. The PDMS microchannel chip was attached to the temperature controlling substrate for reconfigurable thermal applications. A thin PDMS film was used to seal the microchannel and bridge the functionalized substrate and the sample inside the channel, which facilitated heat transferring and prevented sample contaminating the temperature controlling substrate. Demonstrated by a one dimensional thermal resistance model, the thin PDMS film was important for the present reconfiguration applications. Thermal performance of this hybrid microsystem was examined, and the experimental results demonstrated that the chip system could work stably over hours with temperature variation less than 0.1°C. Multiple PDMS microchannel chips were tested on one heating substrate sequentially with a maximum intra-chip temperature difference of 1.0°C. DNA extracted from serum of a chronic hepatitis B virus (HBV) patient was amplified by this hybrid microsystem and the gel electrophoresis result indicated that the present reconfigurable microfluidic scheme worked successfully.