Electrodeposition of polypyrrole–multiwalled carbon nanotube–glucose oxidase nanobiocomposite film for the detection of glucose

A nanobiocomposite film consisted of polypyrrole (PPy), functionalized multiwalled carbon nanotubes (cMWNTs), and glucose oxidase (GOx) were electrochemically synthesized by electrooxidation of 0.1 M pyrrole in aqueous solution containing appropriate amounts of cMWNTs and GOx. Potentiostatic growth profiles indicate that the anionic cMWNTs is incorporated within the growing PPy–cMWNTs nanocomposite for maintaining its electrical neutrality. The morphology of the PPy–cMWNTs nanocomposite was characterized by scanning electron microscopy (SEM). The PPy–cMWNTs nanocomposite was deposited homogeneously onto glassy carbon electrode. The amperometric responses vary proportionately to the concentration of hydrogen peroxide at the PPy–cMWNTs nanocomposite modified electrode at an operating potential of 0.7 V versus Ag/AgCl (3 M). The results indicate that the electroanalytical PPy–cMWNTs–GOx nanobiocomposite film was highly sensitive and suitable for glucose biosensor based on GOx function. The GOx concentration within the PPy–cMWNTs–GOx nanobiocomposite and the film thickness are crucial for the performance of the glucose biosensor. The amperometric responses of the optimized PPy–cMWNTs–GOx glucose biosensor (1.5 mg mL−1 GOx, 141 mC cm−2 total charge) displayed a sensitivity of 95 nA mM−1, a linear range up to 4 mM, and a response time of about 8 s.