Gold Nanoparticles and Multi-wall Carbon Nanotubes for Modification of Glucose Biosensor and Optimization by Application of Taguchi Method

In this paper, multi-wall carbon nanotubes (MWCNTs), gold nanoparticles (GNp) and glucose oxidase (GOD) was developed for the specific detection of glucose. MWCNTs were chemically modified with the H2SO4–HNO3 preatreated to introduce carboxyl groups which were used to interact with the amino groups of poly allylamine (PAA) and cysteamine via 1-ethyl-3-(3 dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide cross-linking reaction, respectively. A cleaned Pt electrode was immersed in PAA, MWCNTs, cysteamine and GNp, respectively, followed by the adsorption of GOD, assembling the one layer of films on the surface of Pt electrode (GOD/GNp/MWCNTs/Pt electrode) and was used as working electrodes (anode) along with a platinum auxiliary electrode and the reference electrode Ag/AgCl (cathode). Working electrode was containing the phosphate-buffered saline (PBS) with pH= 4, 6 and 8 enzyme. To evaluate the performance of the constructed biosensor, it was put into a dish containing 0.05, 0.5 and 1 mmol/l (mM) glucose concentrations which were dissolved in doubly distilled water. Glucose concentration and pH design has been tested and analyzed by QUALTEK-4 software measure. According to the performed experiments and software analysis, with increasing concentration, the flow rate of current production is increased and pH deviance from neutral range reduces the flow. Optimal conditions was obtained in concentrations 1 mmol/l and pH=6, respectively. After confirmation tests in optimum conditions, the rate of production was obtained, 21.67 mA, which with respect to the expected error rate of application, it was calculated to be 8.1%. This error rate demonstrates that the accuracy of tests is with high sensitivity and accuracy.