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

Abstract

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 −0.05V vs. Ag/AgCl in 0.05M phosphate buffer, pH 7.4. The choline biosensor exhibited a high sensitivity of 345.4μAmM−1cm−2 with a detection limit of 4.5×10−7M. The amperometric response was linear from 4.5×10−7 to 1.0×10−4M. The proposed biosensor displayed a short response time of 2s, low Km value of 9.7×10−5M, good storage stability and high selectivity.