ABSTRACT
Abnormal insulin secretion or a lack of effective insulin may lead to hyperglycemia and even diabetes. The detection of insulin can enable better glucose control. This study presents a three-electrode chip fabricated using a printed circuit board for the detection of insulin. The surface of the working electrode was modified with graphene oxide and polyvinyl alcohol (GO-PVA) for electroplating nickel-cobalt alloy. Cyclic voltammetry (CV) measurements were performed using 0.5 μM recombinant human insulin. From the comparison of surface modification methods of electrodes, the CV measurements showed no redox peaks using the bare copper electrode and the Ni-Co electrodeposited copper electrode in the detection of insulin. In contrast, GO-PVA-modified chips, with or without electrodeposited Ni-Co alloy, had redox peaks. This result indicated that GO-PVA promoted the redox reaction, resulting in distinct oxidation and reduction peaks. Moreover, O2-plasma treatment affected the catalytic effect of GO-PVA on insulin. Prior to coating GO-PVA on the working electrode, the bare copper electrode was treated with O2 plasma. The experimental results showed that the electrodeposited Ni-Co alloy chip had a better catalytic effect than the chip without Ni-Co alloy deposited. However, the chip treated again with O2 plasma before electroplating Ni-Co alloy had the best catalytic effect on insulin.
