Temperature-induced amperometric glucose biosensor based on a poly(N-vinylcaprolactam)/graphene oxide composite film

Abstract

A temperature-induced sensing film consisting of poly(N-vinylcaprolactam) (PVCL), graphene oxide (GO) and glucose oxidase (GOD) was fabricated and used to modify a glassy carbon electrode (GCE). The PVCL/GO/GOD/GCE composite film was characterized by electrochemical impedance spectroscopy (EIS). The morphological properties of the composite were investigated by scanning electron microscopy (SEM). The direct electron transfer (DET) of GOD was achieved. GOD at PVCL/GO/GOD/GCE exhibited a couple of well-defined redox peaks with a formal potential of −0.432 V (vs. Ag/AgCl). The composite film showed temperature-induced catalytic activity towards glucose. Large peak currents were observed by amperometry at −0.39 V (vs. Ag/AgCl) when the temperature was above the lower critical solution temperature (LCST) of PVCL, and then disappeared when it was below the LCST. The modified electrode displayed an excellent electrocatalytic response to glucose. The detection of glucose with the composite film ranged from 0.1 to 1.7 mmol L⁻¹ above 35 °C. The constructed biosensor also possesses good stability, reproducibility and anti-interference ability.