Direct electrochemistry of glucose oxidase and biosensing for glucose based on helical carbon nanotubes modified magnetic electrodes

Poly(diallyldimethylammonium chloride) functionalized helical carbon nanotubes (PDDA-HCNTs) were successfully synthesized. The resulting PDDA-HCNTs composite has good conductivity, solubility and ferromagnetic property. The fabricated HCNTs could be conveniently separated and magnetically attached to the magnetic electrode owing to their excellent magnetic properties. An amperometric biosensor was firstly developed based on glucose oxidase (GOD) functionalized PDDA-HCNTs loaded on magnetic glass carbon electrode. The constructed biosensor exhibited excellent electrocatalytic activity and stability for the detection of glucose with a linear range from 5 to 85 μM and a low detection limit of 0.72 μM at 3σ. The present work offers a new avenue to broaden the applications of HCNTs in electrochemical biosensors.