Structure implies function is the mantra of the structural biologists. X-ray diffraction of protein crystals reveals protein structure, which is needed to advance fundamental understanding of protein function and for drug development. Currently the physical process of crystallization is the bottleneck in protein structure determination.

We describe a microfluidic device denoted Phase Chip 1.0, specifically designed to optimize and decouple the mechanisms of nucleation and growth. Phase Chip 1.0 is fabricated with multiple microfluidic components in order to precisely meter, mix, and store nanoliter volumes of sample, solvent, and other reagents. Hundreds of nanoliter drops of different protein solutions can be stored and individually processed using a total of 10 micrograms of protein. While sophisticated microfluidic technology is beguiling, simplicity is a virtue as demonstrated in our second generation design, Phase Chip 2.0.

Movies illustrating the Phase Chip in action are available online.

 http://www.elsie.brandeis.edu/