Reduced graphene oxide modified the interdigitated chain electrode for an insulin sensor

Abstract

Insulin is a key regulator in glucose homeostasis and its deficiency or alternations in the human body causes various types of diabetic disorders. In this paper, we present the development of a reduced graphene oxide (rGO) modified interdigitated chain electrode (ICE) for direct capacitive detection of insulin. The impedance properties of rGO-ICE were characterized by equivalent circuit modeling. After an electrochemical deposition of rGO on ICE, the electrode was modified with self-assembled monolayers and insulin antibodies in order to achieve insulin binding reactions. The impedance spectra and capacitances were measured with respect to the concentrations of insulin and the capacitance change (∆C) was analyzed to quantify insulin concentration. The antibody immobilized electrode showed an increment of ∆C according to the insulin concentration in human serum ranging from 1 ng/mL to 10 μg/mL. The proposed sensor is feasible for label-free and real-time measuring of the biomarker and for point-of-care diagnosis.