Streaming potential--a general affinity sensor

Electrokinetic phenomena, such as streaming potential or streaming current, have so far been used for studies of unspecific adsorption of ionic compounds on various materials. This paper shows that streaming potential measurements can also be used for studies of biospecific interactions. Several different interactions were studied, e.g. lectin-carbohydrate, IgG-Protein A. Regardless of the type of interaction an increasing change in streaming potential was obtained with increasing concentration of the interacting molecule. The authors also observed a correlation between streaming potential and affinity constants for carbohydrate-induced desorption of Concanavalin A from partially hydrolyzed Sephadex G50. In conclusion, it is shown that streaming potential measurements can be used to study molecular interactions, and to determine concentrations and relative binding constants of interacting molecules.