Fig. 3: Microfluidic setup and chamber design.

a Building blocks are loaded into the sample chamber using a microfluidic pressure pump. b Typical distribution of building blocks in one of the sample loading channels during assembly. The building blocks shown in this case are 1 µm polystyrene spheres. This distribution corresponds to the initial distribution, as at later times, sedimentation leads to a reduction in the population density. However, in experiments using the microfluidic pressure pump, building blocks can be replenished by flowing additional solution from the building block suspension reservoirs. c Top view of one of the sample chambers used in this study. The other type of sample chamber, a 5-port configuration, is illustrated in (a). d Exploded view of the sample chamber illustrated in (c). The chamber consists of three layers that are sealed together using a UV-curing adhesive. The thickness of each layer is labeled in the diagram.