title: Research highlights: surface-based microfluidic control.
abstract: Microfluidic systems are often dominated by their surfaces because of the high surface area to volume ratios in microchannel flows or drop-based systems. Here we highlight recent work on engineering and exploiting surface effects to control the formation and motion of microdrops. We highlight work using precisely microstructured wetting surfaces to repel all manner of liquids even when the liquid-air surface tension is low. In a second paper, selective capillary filling and draining is used to pattern liquid and cell-laden gels for 3D culture. A final paper making use of vapor-driven surface tension effects to drive the motion of drop ensembles is also examined, exploring a new mechanism for drop control - including motion and merging. Surface-driven motion and patterning has been a widely successful area in microfluidics (e.g. electrowetting or patterned self-assembled monolayers) and recent work is extending into new directions that, once well-understood, should enable new applications.
authors.affiliation: Department of Bioengineering, University of California, Los Angeles, CA 90095, USA. dicarlo@ucla.edu.
authors.forename: Oladunni
authors.initials: O
authors.lastname: Adeyiga
authors.forename: Soroush
authors.initials: S
authors.lastname: Kahkeshani
authors.forename: Petra
authors.initials: P
authors.lastname: Paiè
authors.forename: Dino
authors.initials: D
authors.lastname: Di Carlo
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation; D045744:Cell Line, Tumor; D004867:Equipment Design; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D013499:Surface Properties; D013500:Surface Tension