Thermophoresis in protein solutions
Abstract
Thermophoresis, unlike thermal diffusion in simple mixtures, consists in particle drift induced by a temperature gradient ∇T. We show that thermophoresis in lysozyme solutions has a very distinctive behavior: particle motion can indeed be tuned from "thermophobic" (towards the cold) to "thermophilic" (along ∇T) by decreasing T. The observed temperature behaviour weakly depends on electrostatic effects, and rather suggests a primary role of hydrophobic interactions, further supported by comparison with the temperature dependence of lysozyme equilibrium solubility. Most of the observed features can be qualitatively understood by envisaging thermophoresis as a "microscopic Marangoni effect", due to thermally induced gradients of the interfacial free energy.
- Publication:
-
EPL (Europhysics Letters)
- Pub Date:
- July 2003
- DOI:
- 10.1209/epl/i2003-00520-y
- Bibcode:
- 2003EL.....63..247I
- Keywords:
-
- 66.10.Cb;
- 82.70.Dd;
- 87.15.Nn;
- Diffusion and thermal diffusion;
- Colloids;
- Properties of solutions;
- aggregation and crystallization of macromolecules