Systematic Investigation of Protein Phase Behavior with a Microfluidic Formulator

Carl L. Hansen, Morten Otto Alexander Sommer, Stephen R. Quake

Research output: Contribution to journalJournal articleResearchpeer-review


We demonstrated a microfluidic device for rapidly generating complex mixtures of 32 stock reagents in a 5-nl reactor. This "formulation chip" is fully automated and allows thousands of experiments to be performed in a single day with minimal reagent consumption. It was applied to systematically study the phase behavior of the protein xylanase over a large and complex chemical space. For each chemical formulation that demonstrated a pronounced effect on solubility, the protein phase behavior was completely mapped in the chip, generating a set of empirical phase diagrams. This ab initio phase information was used to devise a rational crystallization screen that resulted in 72-fold improvement in successful crystallization hits compared with conventional sparse matrix screens. This formulations tool allows a physics-based approach to protein crystallization that may prove useful in structural genomics efforts.
Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number40
Pages (from-to)14431-14436
Number of pages6
Publication statusPublished - 2004
Externally publishedYes


  • Biophysical Phenomena
  • Biophysics
  • Chemical Precipitation
  • Crystallization
  • Endo-1,4-beta Xylanases
  • Microfluidics
  • Proteins
  • Solubility
  • Spectrophotometry
  • Trichoderma
  • Caltech Library Services


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