A highly sensitive choline biosensor based on bamboo-like multiwall carbon nanotubes/ionic liquid/Prussian blue nanocomposite

• A new nanocomposite consist of bamboo like carbon nanotube, ionic liquid and Prussian blue nanoparticles was used for choline detection via reduction of hydrogen peroxide produced by choline oxidase.
• Ni2+ ions were electrochemically incorporated into the Prussian blue structure to improve its stability in alkaline media.
• The biosensor shows good analytical characteristics such as high sensitivity of 345.4 μA mM−1 cm−2, short response time of 2 s, low Km value and high selectivity.

A highly sensitive amperometric choline biosensor was fabricated using bamboo-like multi-walled carbon nanotubes (BCNTs)/ionic liquid (IL)/Prussian blue (PB) nanocomposite modified glassy carbon (GC) electrode. The PB nanoparticles were first electrodeposited on the surface of a BCNTs/IL/GC electrode. The Ni2+ ions were then electrochemically incorporated into the PB structure to improve its stability in mild alkaline media. Choline oxidase was next immobilized on the modified electrode using a cross-linking method. Amperometric measurements of choline were performed at −0.05 V vs. Ag/AgCl in 0.05 M phosphate buffer, pH 7.4. The choline biosensor exhibited a high sensitivity of 345.4 μA mM−1 cm−2 with a detection limit of 4.5 × 10−7 M. The amperometric response was linear from 4.5 × 10−7 to 1.0 × 10−4 M. The proposed biosensor displayed a short response time of 2 s, low Km value of 9.7 × 10−5 M, good storage stability and high selectivity.