Microfluidic polymerase chain reaction (PCR) has been of great interest owing to its ability to perform rapid and specific nucleic acid amplification and analysis on small volumes of samples. One of the major drawbacks of microfluidic PCR is bubble generation and reagent evaporation, which can cause malfunctions. Here, we propose a bubble-free microfluidic PCR device via controlled fluid transfer. We design the PCR chamber surrounding circumferential chamber allows a guided-fluid transport of generated bubble to circumferential chamber through thin nanoporous PDMS sidewall. We accomplish the theoretical modeling of formation bubble behavior and removal of bubbles. We solve the generation of bubbles by inhibiting mass transport along a vertical direction via a thin impermeable polyethylene (PE) as a top layer, and the fast gas transport through the circumferential ring barrier of nanoporous poly(dimethylsiloxane). We demonstrate stand- alone self-powered sample loading and the guided-fluid transport of bubble escapement during thermal cycling, and accomplish the successful amplification of the cMET gene, a nucleic acid (NA) biomarker for lung cancer. In addition, an ultrafast digital PCR test on chip was completed in less than 3 min using a high powered Peltier-based thermal cycler without bubbles. This approach will result in a new paradigm for ultrafast molecular diagnosis on chip and can facilitate NA-based nearly instantaneous diagnostics for point- of-care testing and for personalized and preventive medicine.
Project end date: 02/01/16