A benzimidazole-based conducting polymer and a PMMA–clay nanocomposite containing biosensor platform for glucose sensing

• Different immobilization platforms using PMMA–clay nanocomposite.
• A conducting polymer; poly(BIPE) were tested for the detection of glucose.
• Aromatic units of polymer play an important role on the interaction with biomolecule.
• Nanocomposite is a protective matrix for retention of 3-D conformation of enzyme.
• Combined use of PMMA–clay nanocomposite and poly(BIPE) leads to remarkable results.

Development of materials composed of polymer–clay nanocomposites (PCN) and conducting polymers attracts great interest and preferred in various applications. Hereby, polymethylmethacrylate (PMMA) layered silicate nanocomposites were prepared by in-situ suspension polymerization by grafting PMMA with laponite using a suitable grafting agent. The properties of the as-synthesized PCN materials are characterized by differential scanning calorimetry (DSC), thermal gravimetry analysis (TGA) and gel permeation chromatography (GPC). A conducting polymer; poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-7-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)-2-benzyl-1H-benzo[d]imidazole) (poly(BIPE)) and a PMMA–clay nanocomposite with 2-(methacryloyloxy) ethyltrimethylammonium chloride (MTMA) modifier were examined as a platform for biomolecule deposition. Glucose oxidase (GOx, β-d-glucose: oxygen-1-oxidoreductase, EC 1.1.3.4) was chosen as the model enzyme to prepare a scaffold for glucose sensing. Three different sensing strategies; PCN/GOx, poly(BIPE)/GOx and PCN/poly(BIPE)/GOx were analyzed and their biosensor performances were discussed. Surface morphology of the modified electrodes was characterized by scanning electron microscopy (SEM) technique. Electrochemical responses of the enzyme electrodes were monitored at −0.7 V vs. Ag reference electrode by monitoring oxygen consumption in the presence of glucose. After optimum conditions were determined, kinetic and analytical parameters; KMapp, Imax, LOD and sensitivity were investigated for each sensing platform.

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