Development of Insulin Sensors Based on Faradaic and Non-Faradaic Electrochemical Impedance Spectroscopy Detection Principle Using Single Chain Antibody (scFv)

摘要

In this paper, we report novel insulin sensors using insulin single-chain antibody (scFv) based on two electrochemical impedance spectroscopy (EIS) methods; faradaic EIS and non-faradaic EIS. For faradaic EIS measurement, varieties of molecular recognition elements (MREs) can be utilized, such as IgG and binding proteins, without consideration of their molecular size. However, a solubilized redox probe is necessary to aid the transfer of electrons and detection is based on the flux of electrons and the obstruction that is present on the electrode surface. Non-faradaic EIS does not require a solubilized redox probe and is based around changes within the electrical double layer. However, there are the limitation of the size for MREs, since the ideal size of MREs should be smaller than the size of electrical double layer (EDL). In this paper, thanks to the small size of scFv as MRE for EIS, we construct two different types of EIS based insulin sensors, and compare the suitability in the use for insulin monitoring, being dedicated for the management of diabetic patients.