A sensitive choline biosensor using Fe3O4 magnetic nanoparticles as peroxidase mimics.

A sensitive choline biosensor using Fe(3)O(4) magnetic nanoparticles and a choline oxidase modified gold electrode was developed. Fe(3)O(4) magnetic nanoparticles as peroxidase mimics used in the choline biosensor can not only improve the sensitivity of the response signal, but also possess the favorable properties of stability, magnetic separation and easy preparation, etc. When using the reduction currents of square wave voltammetry as the detection signals, the interferences of ascorbic acid and uric acid to the choline biosensor can be reduced effectively. The reduction currents of the square wave voltammetry were increased with the logarithm values of the choline chloride concentration (from 10(-9) to 10(-2) M), the detection limit was estimated to be 0.1 nM (S/N = 3). This choline biosensor also exhibited favorable selectivity and stability in the determination of choline chloride.