Fabricating dynamic microfluidic structures can be challenging.  In Byoung Choul and Chris’ latest work, adjustable microfluidic channels with defined dimensions and positions can be created by simply stretching and fracturing a multilayered material.  In this technique, a film of brittle silicone is sandwiched between two tough silicone layers, and stretched.  The modulus and toughness mismatch between the materials causes the brittle layer to fracture in a well-defined pattern.  The fracture forms an adjustable microfluidic channel, which is completely reversible:  it seems that breaking up is not that hard to undo.  We used this technique to trap single cells within an adjustable microchannel, mechanically lyse them during channel collapse, and linearize the released nuclear chromatin for epigenetic analysis.  Please see publications for more information.