Figure 2.

Chamber channels and DNA hairpin designs. (a) Scheme of the old (upper panel) and new (lower panel) microfluidics chamber designed to prevent convection. The new design employs two coverglasses (24 × 60 mm, #2; VWR 48382-139) and one Nescolfilm layer (instead of two as in the old design). With this design, the microchamber thickness is reduced from 180 to 110 μm. The channel design was modified to avoid obstruction of the lower channel by the micropipette (∼80 μm in diameter). The central channel holds the micropipette in the dome (this cavity typically is 2 mm high and 1.8 mm wide). The direction of the flow, which is stopped during an experiment, is marked by IN and OUT labels. The top and bottom channels, connected to the main channel through dispenser tubes, are used to flow different types of beads and to control the concentration and flow speed at their entrance to the dome of the central channel. (b) Design of the 6.8 kb sequence. Details are provided in the Supporting Material. To see this figure in color, go online.