Frequency-dependent electrical detection of protein binding events

Publisher Website
Google Scholar
Abstract
Frequency-dependent electrochemical impedance spectroscopy has been used to characterize the changes in electrical response that accompany specific binding of a protein to its substrate, using the biotin–avidin system as a model. Our results show that avidin, at concentrations in the nanomolar range, can be detected electrically in a completely label-free manner under conditions of zero average current flow and without the use of any auxiliary redox agents. Impedance measurements performed on biotin-modified surfaces of gold, glassy carbon, and silicon were obtained over a wide frequency range, from 5 mHz to 1 MHz. On each biotin-modified surface, binding of avidin is most easily detected at low frequencies, <1 Hz. Electrical circuit modeling of the interface was used to relate the frequency-dependent electrical response to the physical structure of the interface before and after avidin binding. Electrical measurements were correlated with measurements of protein binding using fluorescently labeled avidin.

This publication has 0 references indexed in Scilit: