Thermophoresis

Thermophoresis (also thermomigration, thermodiffusion, the Soret effect, or the Ludwig–Soret effect) is a phenomenon observed in mixtures of mobile particles where the different particle types exhibit different responses to the force of a temperature gradient.

[3] Thermodiffusion is labeled "positive" when particles move from a hot to cold region and "negative" when the reverse is true.

Recently, Braun and coworkers have suggested that the charge and entropy of the hydration shell of molecules play a major role for the thermophoresis of biomolecules in aqueous solutions.

The basis for applications is that, because different particle types move differently under the force of the temperature gradient, the particle types can be separated by that force after they have been mixed together, or prevented from mixing if they are already separated.

The diffusive flux may occur in either direction (either up or down the temperature gradient), dependent on the materials involved.

Thermophoresis has also been shown to have potential in facilitating drug discovery by allowing the detection of aptamer binding by comparison of the bound versus unbound motion of the target molecule.

[8][9] Furthermore, thermophoresis has been demonstrated as a versatile technique for manipulating single biological macromolecules, such as genomic-length DNA, and HIV virus[10][11] in micro- and nanochannels by means of light-induced local heating.

[12] Thermophoresis is one of the methods used to separate different polymer particles in field flow fractionation.

[14] Thermophoresis in liquid mixtures was first observed and reported by Carl Ludwig in 1856 and further understood by Charles Soret in 1879.