The microfluidic device, schematics of the sandwich hybridization, and laminar flow-assisted dendritic amplification (LFDA).

<p>(A) The microfluidic device. (B) The photomask used to fabricate the silicon mold. The ladder shaped pattern on both sides of the double-Y channels was designed as a ruler for general purposes. In this study, a part of it was used for alignment of the PDMS channel with the probe DNA pattern. The detours of the center channels were constructed to make the fluidic resistances, proportional to the channel length, uniform in all of the four branches. (C) Schematics of the power-free microfluidic device. PDMS absorbs air in the outlet chamber, thus being a self-stand pumping device. The width of the DNA probe pattern was 100 µm, and it was located 500 µm downstream of the confluent point of the Y-shaped channel. (D) Enlarged view of a laminar flow in the microchannel. F-SA and B-anti-SA are conveyed by the laminar flow. (E) Enlarged cross-sectional view of the sandwich hybridization and LFDA. The dendritic amplification takes place at the intersection between the probe DNA patterned surface and the interface of the laminar flow. F-SA: FITC-labeled streptavidin, B-anti-SA: biotinylated anti-streptavidin.