Probing the Mechanism of Aqueous Two-Phase System Formation for α-Elastin On-Chip

Yanjie Zhang, Hanbin Mao, Paul S. Cremer

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21 Scopus citations


The kinetics of formation of the aqueous two-phase system (ATPS) for α-elastin was studied by dark field microscopy in an on-chip linear temperature gradient. Scattering intensities of protein solutions were recorded as a function of temperature and time, simultaneously at several concentrations. It was found that the formation rate of the ATPS could be fit as a first-order process and that the apparent rate constant increased with protein concentration. The activation energy for the process was 9.5 ± 0.5 kcal/mol, and this result was consistent with a coalescence mechanism. Experiments were also conducted with varying concentrations of sodium dodecyl sulfate, which shut off the coalescence mechanism forcing ATPS formation to proceed through Ostwald ripening. When this was done, the activation energy increased to 33 ± 2 kcal/mol and the kinetics became consistent with a second-order process.

Original languageEnglish (US)
Pages (from-to)15630-15635
Number of pages6
JournalJournal of the American Chemical Society
Issue number50
StatePublished - Dec 17 2003

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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