Non-invasive Detection of Glucose via Solution-Gated Graphene Transistor
Owing to the high sensitivity, solution-gated graphene transistor has emerged as the cutting edge technology in the area of electrochemical sensing. In this work, composites of gold nanoparticles and reduced graphene oxide were synthesized by using the electrodeposition method on a glassy carbon electrode. The modified glassy carbon electrode was used as the gate electrode and assembled into the solution-gated graphene transistor device along with the graphene channel for non-invasive glucose detection. The sensing mechanism is based on the current changing in the channel of the device caused by the adding of glucose, of which the electro-oxidation on the surface of the gold nanoparticles and reduced graphene oxide leads to the change of equivalent gate voltage and consequently affected the channel carrier concentration. The self-amplification effect of transistors has been utilized in our sensor resulting in a detection limit of 10 times lower than those of conventional electrochemical sensors. Compared to the traditional enzymatic transistor sensors, the novel solution-gated graphene transistor nonenzymatic sensor based on gold nanoparticles and reduced graphene oxide showed significant sensing advantages, such as simple structure, wide linear range from 10 μM to 1 mM and 1 mM to 31 mM and lower detection limit down to 4 μM. The chemicals coexisting in the human sweat e.g. sodium chloride, urea and lactic acid imposed no distinct interference for the glucose detection. Therefore, we achieved non-invasive detection of glucose in artificial sweat samples with satisfactory sensing results. This work demonstrates an effective way for non-invasive glucose testing in practical clinical diagnosis by using nonenzymatic solution-gated graphene transistor devices.