Marangoni flows drive the alignment of fibrillar cell-laden hydrogels
When a stationary droplet containing a solute in a volatile solvent evaporates, the flow in the droplet can assemble into complex patterns. Researchers have examined such transport in evaporating sessile droplets in solvents. In a new report now published on Science Advances, Bryan A. Nerger and a team of scientists in chemical and biological engineering, and molecular biology at the Princeton University, U.S., demonstrated flow in evaporating aqueous sessile droplets containing the self-assembling polymer type I collagen. The material can be used to engineer hydrated networks of aligned collagen fibers. The team noted the Marangoni effect (a term originating from the spread of oil droplets on water) to direct the assembly of collagen fibers across millimeter-scale areas relative to environmental humidity and the geometric shape of the droplet. Nerger et al. incorporated and cultured skeletal muscle cells into the evaporating droplets to observe their collective orientation and subsequent differentiation to...