Fabrication of polymeric ionic liquid/graphene nanocomposite for glucose oxidase immobilization and direct electrochemistry

Abstract

A novel polymeric ionic liquid functionalized graphene, poly(1-vinyl-3-butylimidazolium bromide)-graphene (denoted as poly(ViBuIm +Br −)-G), was synthesized. FTIR, UV–vis spectra and TEM were used to characterize the formation of as synthesized nanocomposites. Due to the modification of the polymeric ionic liquid, poly(ViBuIm +Br −)-G can not only be dispersed well in aqueous solutions to form a homogeneous colloidal suspension of individual nanosheets, but also exhibit a strong positive charge. Based on self-assembly, the negatively charged glucose oxidase (GOD) was immobilized onto the poly(ViBuIm +Br −)-G to form a GOD/poly(ViBuIm +Br −)-G/glassy carbon (GC) electrode under mild conditions. With the advantage of both poly(ViBuIm +Br −) and graphene, poly(ViBuIm +Br −)-G can provide a favorable and conductive microenvironment for the immobilized GOD and thus promote their direct electron transfer at the GC electrode. Furthermore, the GOD/poly(ViBuIm +Br −)-G/GC electrode displayed an excellent sensitivity, together with a wide linear range and excellent stability for the detection of glucose. Accordingly, these unique properties of such novel nanocomposite generate a promising platform for the construction of mediator-free enzymatic biosensors.