An electrochemical biosensor for fructosyl valine for glycosylated hemoglobin detection based on core–shell magnetic bionanoparticles modified gold electrode

A high-performance amperometric fructosyl valine (FV) biosensor was developed, based on immobilization of fructosyl amino-acid oxidase (FAO) on core–shell magnetic bionanoparticles modified gold electrode. Chitosan was used to introduce amino groups onto the surface of core–shell magnetic bionanoparticles (MNPs). With FAO as an enzyme model, a new fructosyl valine biosensor was fabricated. The biosensor showed optimum response, when operated at 50 mV s−1 in 0.1 M potassium phosphate buffer, pH 7.5 and 35 °C. The biosensor exhibited excellent sensitivity [the detection limit is down to 0.1 mM for FV], fast response time (less than 4 s), wide linear range (from 0 to 2 mM). Analytical recovery of added FV was 95.00–98.50%. Within batch and between batch coefficients of variation were <2.58% and <5.63%, respectively. The enzyme electrode was used 250 times over 3 months, when stored at 4 °C.