GO platelets were gathered after drying the suspension. TRGO were synthesized by the hydrothermal reduction process. Briefly, a solution of GO was prepared in deionized (DI) water at a concentration of 2 mg/mL. Then, a certain amount of 1.5 M AA solution was added in the as-prepared GO solution to prepare the final mixture with a concentration of 0.4 M. Finally, the solution was sealed in an autoclave and heated up at 180 °C for 1.5 h. After cooling the autoclave to room temperature, the as-developed TRGO solution was added in 1 M aqueous sulfuric acid solution and left overnight. Afterwards, the solution mixture was filtered, cleaned several times with DI water, and dried for several hours at 95 °C in a vacuum …show more content…
1(A). Glucose sensor was designed with three different electrodes, a counter electrode (PtNP), a reference electrode (Ag/AgCl), and working electrodes (TRGO/PtNP/chit-GOx/nafion). The fabrication steps of the proposed enzymatic glucose biosensors on Si/SiO2 substrate are shown in Fig. 1(B). After sputtering Ti and Au films on top of the SiO2 layer, it was patterned to have three different electrodes by the wet-etching technique. TRGO powder (23 mg) was added in a mixture of DMF and DI water (1:1) solution, and then the solution was dispersed under ultrasonication at 200 W for 3 h. The as-prepared TRGO dispersion solution (6 μL) was cast on the electrodes surface and dried under ambient conditions. Afterward, TRGO was electrochemically etched away from the counter and reference electrodes. This was easily performed by cyclic voltammetry (CV). Different potential windows were applied for etching TRGO without damage of the working electrodes and make higher resistance among the three electrode gaps. The method is described in the subsequent section. The PtNP was simultaneously deposited on the top of the TRGO modified working electrodes and counter electrode by CV (Electrochemical analyzer, CHI 660D) under potential from –0.35 to 0.7 V in a deaerated precursor solution consisting of 2.5 mM of H2PtCl6 and 0.1 M of KCl for 10 and 14 cycles, respectively. Then, the modified electrodes were cleaned