Graphene oxide/gold nanoparticle/graphite fiber microelectrodes for directing electron transfer of glucose oxidase and glucose detection

A promising electrochemical sensor is investigated using graphene oxide (GO)/gold nanoparticle (AuNP)-modified graphite electrodes to enhance charge transport in electrochemical biosensors and increase the sensitivity for glucose detection. An efficient charge transfer pathway is formed by interconnected GO nanosheets and AuNP along the graphite fiber (GF) electrode (GFE). The positive GO can adsorb glucose oxidase (GOD) by electrostatic attraction. The detected response current of the sensor is linearly related to the glucose concentration within a detection limit of 1.2 μM. Furthermore, this glucose sensor has high stability, good reproducibility and excellent selectivity for various oxidizable molecules such as dopamine (DA), uric acid (UA), ascorbic acid (AA) and other molecules causing chaff interference (fructose, lactose and galactose). It is worth noting that this work shows a new method using covalent bonds and self-assembly on the surface of GF for fabricating excellent electrochemical glucose biosensors.