Amine-terminated ionic liquid functionalized carbon nanotube-gold nanoparticles for investigating the direct electron transfer of glucose oxidase

A novel nanocomposite was fabricated by three steps. In the first step, a chemical route was adopted to functionalization single-walled carbon nanotube (SWNT) with a new amine-terminated ionic liquid (NH2-IL) to form IL-SWNT composite. In the second step, gold nanoparticle (GNP) was electrodeposited onto IL-SWNT to prepare GNP-IL-SWNT nanocomposite. In the last step, IL-GNP-IL-SWNT nanocomposite was obtained by self-assembly NH2-IL on GNP. Glucose oxidase (GOD) was assembled on this novel composite through ionic interaction and achieved its direct electrochemistry. A pair of well-shaped voltammetric peaks was observed with the formal potentials (E0′) at −0.501 V. The GOD modified electrode also exhibited an excellent electrocatalytic activity to the reduction of glucose with a detection limit of 0.8 μmol/L (S/N = 3). The apparent Michaelis–Menten constant (Kmapp) was estimated to be 0.022 mM. This protocol had potential application to fabricate the third-generation biosensor.