Biosensors Based on Carbon Nanotubes/Nickel Hexacyanoferrate/Glucose Oxidase Nanocomposites

Novel hybrid films based on carbon nanotubes (CNTs)/nickel hexacyanoferrate (NiHCF) nanocomposites were synthesized, characterized, and evaluated for chemical and bio-sensing properties. Nickel hexacyanoferrate particles were electrodeposited on the porous CNT thin-film to fabricate electrochemical sensors with improved sensitivity to H2O2. Transmission electron microscopy illustrated the deposition of nickel hexacyanoferrate nanoparticles on the surface of carbon nanotubes. The experimental results show the electrode modified with the hybrid nanocomposite film has higher electrocatalytic activity and stability for detection of H2O2 than the electrodes modified with carbon nanotube or nickel hexacyanoferrate alone. With glucose oxidase (GOx) as an enzyme model, we constructed a biosensor based on the CNTs/NiHCF/GOx nanocomposite. An excellent linear relationship up to 1.2 mM has been obtained with a slope of 5.3 mu A/mM for the glucose biosensor. The response time and detection limit (S/N = 3) of the biosensor was determined to be 10 s and 1 mu M, respectively. The high sensitivity to glucose of the biosensor resulted from the high surface area of carbon nanotubes and excellent electrocatalytic activity of the modifiers. The biosensor also performed with excellent reproducibility and good stability.