Poly(GMA-co-VFc)/Fe₃O₄/cholesterol oxidase bionanocomposite based electrodes for amperometric cholesterol biosensor

A highly sensitive cholesterol biosensor was fabricated using poly(GMA-co-VFc)/MNP and cholesterol oxidase. The enzyme was immobilized on to glassy carbon electrode surface using poly(GMAco- VFc) redox polymer containing super paramagnetic iron oxide nanoparticles (MNPs), which greatly enhanced electron transport between electrode and enzyme, giving a biosensor very good sensitivity, 47 μA mM^-1, linear range of 0.01-0.12 μM, a detection limit of 0.005 μM and incredible response time of 1 s. The biosensor retained 70% of its original response after 18 days, when stored in 0.1 M PBS (pH 7.0) at 4 °C, and it losses 18% of its initial activity in 20 continues assays.