A Novel Label Free Electrochemical Magnetoimmunosensor for Human Interleukin‐6 Quantification in Serum

A novel magnetoimmunosensor, designed for sensitive and selective quantification of interleukin 6, is herein reported. The experimental design involves the covalent immobilization of anti‐interleukin 6 antibody through an amidic bond formed with the carboxyl functionalities provided at the surface of protein G‐functionalized magnetic microparticles, assuring a sandwich‐type immunoassay with electrochemical label free detection. All the experimental parameters involved in the elaboration and testing protocol were optimized. A linear calibration plot between the charge transfer resistance and the logarithmic concentration of interleukin‐6 was achieved in the 1 pg mL −1 to 1 μg mL −1 range. A limit of quantification of 1 pg mL −1 and a detection limit of 0.3 pg mL −1 were obtained. The optimized magnetoimmunosensor showed an excellent selectivity against some potentially interfering proteins and has been successfully applied for the determination of target protein in human serum, proving its clinical relevance.