Dielectric spectroscopy of molecular interactions based on the avidin-biotin complex

Abstract

Dielectric spectroscopy is used to probe the electrical properties of biomolecules dissolved in liquids. A 40 μl cell is constructed out of acrylic with polished, stainless steel electrodes. Experiments are performed on avidin and biotin-labeled BSA, showing characteristics of aggregation. Experiments with avidin and biotin demonstrate shifts in dielectric relaxation of the avidin associated with changes in the dipole moment and size of the molecule due to biotin binding. These shifts are analyzed in the context of biomolecular changes. These experiments demonstrate the utility of impedance spectroscopy to detect changes due to small molecules binding to proteins.