Microscale Thermophoresis

Microscale thermophoresis is based on the detection of a temperature-induced change in fluorescence of a target as a function of the concentration of a non-fluorescent ligand. Two distinct effects contribute to the fluorecence signal: a temperature induced change of fluorescence quantum yield of the dye (temperature dependent intensity change, TRIC) and the directed movement of molecules in a temperaure gradient (thermophoresis) which depend on molecular interactions of the fluorescent target molecule with a ligand. In contrast to SPR, interactions are measured in solution thus there are no problems with immobilisation and unspecific adsorption at the chip surface. Measurements are conducted in glass capillaries consuming only a few µL of solution. Disadvantages of the method are the need of a fluorescence dye that can interfere with the measurement and requires labeling of one of the interaction partners, and the fact that two effects contribute to the MST signal.