A functional immobilization matrix based on a conducting polymer and functionalized gold nanoparticles: Synthesis and its application as an amperometric glucose biosensor

Combination of nanoparticles and biomolecules attracted considerable attention in biosensing applications. In this study, effective surface design was investigated by modifying the electrode surface with pristine and functionalized gold nanoparticles. For this purpose, spherical gold nanoparticles were synthesized and characterized with UV–vis spectroscopy and transmission electron microscopy (TEM) analyses. Then, gold nanoparticles were modified with mercaptopropionic acid (MPA) yielding Au–S bonds (Au NPs/MPA). Moreover, a novel functional monomer, 6-(4,7-bis(2,3-dihydrothieno [3,4-b][1,4]dioxin-5-yl)-2H-benzo[d][1,2,3]triazol-2-yl)hexan-1-amine (BEDOA-6), was synthesized and used as an immobilization matrix for glucose biosensor. After successful electrochemical deposition of the polymer; poly(BEDOA-6) on graphite electrodes, immobilization of glucose oxidase (GOx) was carried out covalently with the help of crosslinking agent. During immobilization, Au NPs and Au NPs/MPA were used in biosensor fabrication in order to achieve the most effective surface design for target biosensor. In addition, SEM and fluorescence analyses were utilized to characterize the surface properties. The biosensor shows a wide linear range between 0.025 mM and 1.25 mM glucose concentration with a low detection limit of 0.025 mM. Also, kinetic parameters, operational and storage stabilities were determined. Finally, the biosensor was tested on beverages for glucose detection.