One of the most fun things about microfluidics is watching them in action.
Reminiscent of the famous (well, famous within microfluidics circles) 1999 Science cover by Felice Frankel and the Whitesides group, this video from the Folch lab demonstrates theconcept of laminar flow that typically occurs in microfluidic channels due to the small channel dimensions. At the microfluidic scale, familiar liquids like water behave differently from how we experience them at the kitchen-sink scale.
Not only is laminar flow beautiful to watch, it’s also useful. Many microfluidic devices use laminar flow as an integral part of their function. For example, in 2003 Shuichi Takayama and others in the Whitesides lab used laminar flow to selectively deliver liquid to one side of a cell, a potentially useful tool for a biologist wanting to probe a localized portion of a cell. Photos D-F show the green solution–a mitochondrial stain–moving through the cell over time:
Image credit: Shuichi Takayama, Emanuele Ostuni, Philip LeDuc, Keiji Naruse, Donald E. Ingber and George M. Whitesides
Interestingly, in 2009 a similar theme popped up in Takayama’s research, but instead of applying this technique to a single cell, they applied it to a colony of human embryonic stem cells.
Image credit: Luis Gerardo Villa-Diaz, Yu-suke Torisawa, Tomoyuki Uchida, Jun Ding, Naiara Correa Nogueira-de-Souza, Kathy Sue O'Shea, Shuichi Takayama and Gary Daniel Smith