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.