A Biocompatible Nanocomposite for Glucose Sensing

A nanocomposite containing amine functionalized multiwalled carbon nanotubes and a room temperature ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) was prepared and applied for glucose oxidase (GOx) immobilization on glassy carbon electrode. The proposed nanocomposite provided a favorable microenvironment to preserve the bioactivity of GOx. It could also effectively facilitate the enzyme direct electron transfer to the electrode. This brought about a remarkable improvement in the sensitivity of the glucose biosensor. Under the optimum experimental conditions, the formal potential of GOx was about −467.5 mV. Moreover, the sensitivity and response time of the biosensor toward glucose were 1277 μA mM-1 cm-2 and 6 s, respectively. The biosensor provided a linear dynamic response between 0.1 and 43 μM with a very low detection limit of 63 nM. Also, the values for apparent Michaelis-Menten constant and maximum current were obtained as 18 μM and 2.7 μA, respectively