Preparation Of Grapheme-based Composite Detecting Heads And Their Application In Glucose Sensors

Diabetes is one of the most frequently occurring diseases seriously harmful to humanhealth. Due to it’s quickly and accurately detection of glucose levels in human body blood,glucose sensors has been favored by researchers. But the low sensitivity and expensiveelectrode material suppressed the popularization and application of glucose biosensor. In thispaper, grapheme-based composite detecting heads was prepared by attaching nano gold(AuNPs), reduced graphene oxide (RGO) and enzymes on copper sheet, then, the compositedetecting heads was assembled to form sensor for the determination of glucose. With lowercost, higher stability, simply maintenance and scalable application, the grapheme-basedglucose sensors had wide application prospects.Firstly, graphene oxide (GO) was prepared by modified hummers method, then throughalkaline-microwave-assistance we obtained RGO, and the structure of GO and RGO wascharactered. Results showed that large amount of functional groups such as C-OH, C-O-C,C=O, were appeared on GO, after reduction by alkaline-microwave-assistance, theseoxygen-containing functional groups on RGO decreased rapidly. With black color, the RGOwas dispersed uniformity in water, and was found to remain stable without visible precipitatefor more than one month. The surface of RGO was rough and l amella abrupt, and the (002)interlayer spacing was0.410nm.Secondly, AuNPs was prepared by using sodium citrate reduction method, afterultrasonic mixed with RGO, the result RGO/AuNPs and glucose oxidase were coated on thesurface of copper sheet to get the grapheme-based composite detecting heads, then, thestructure and performance of the grapheme-based composite detecting heads wascharactered.The results showed that some AuNPs particles were embedded in the RGO, while theothers were wrapped in the RGO. With the coating of RGO/AuNPs, the resistance of thecopper sheet was decreased. The grapheme-based composite detecting heads has fasterelectron transfer rate, in the50-700mV.s-1range, the square root of the peak current and scanrate had good linear relationship. The grapheme-based glucose sensor had good electrochemical catalytic behavior to glucose, showed a linear response to glucose in theconcentration range from0.02to6.5mmol.L-1with a detection limit of6.7μmol.L-1,indicating that it has good stability and selectivity.