Glucose sensing by a glassy carbon electrode modified with glucose oxidase and a magnetic polymeric nanocomposite

Abstract

In this paper a synthetic nanocomposite based on poly(p-phenylenediamine) (PPD) and Fe₃O₄ nanoparticles (Fe₃O₄ NPs) introduced as a suitable substrate for enzyme immobilization. Glucose oxidase (GOD) was immobilized on PPD@Fe₃O₄ modified glassy carbon electrode (GCE). The immobilized GOD on PPD@Fe₃O₄ nanocomposite displayed a pair of well-defined quasi-reversible redox peaks with a formal potential of −0.41 V (vs. SCE) and a heterogeneous electron transfer rate constant (k_s) of 3.76 s⁻¹ in 0.1 M pH 7.0 PBS solution. The apparent Michaelis–Menten constant of the immobilized GOD was 0.42 mM, indicating an excellent catalytic activity and a notable affinity to detection of glucose. There was no interference from compounds commonly found in clinical samples and determination of glucose in clinical samples was successfully presented.