Comparative study of enzymatic and non-enzymatic detection of glucose using manganese ferrite nanoparticles

Abstract

The use of metal oxide nanoparticles for the development of cost-effective glucose biosensors has been receiving increased attention. Enzymatic and non-enzymatic glucose sensor using polyethylene glycol (PEG) grafted manganese ferrite (PEG-MnFe _2 O _4 ) nanoparticles (NPs) modified onto a glassy carbon electrode (GCE) is reported in the present study. XRD and Raman studies confirmed the cubic spinel structure of MnFe _2 O _4. The immobilization of glucose oxidase (GOx) on PEG-MnFe _2 O _4 (GOx@PEG-MnFe _2 O _4 ) was validated using FTIR and TGA. Sensing electrodes exhibited well-defined redox peaks in 0.1 M phosphate buffered saline (PBS) solution at pH 7.4 against the reference electrode Ag/AgCl. GOx@PEG-MnFe _2 O _4 /GCE displayed a sensitivity of 1.985 μ A mM ^−1 cm ^−2 in the linear range of 1 to 20 mM with a limit of detection (LOD) of 0.132 mM whereas non-enzymatic sensor exhibited a sensitivity of 1.044 μ A mM ^−1 cm ^−2 in the linear range of 1 to 10 mM with a LOD of 0.099 mM. The lower Michaelis constant ( ${K}_{m}^{app}$ ) value indicates greater affinity towards glucose for the enzymatic sensor. GOx@PEG-MnFe _2 O _4 revealed selectivity specifically for glucose over various interferants such as fructose, lactic acid, sucrose, uric acid and ascorbic acid. In addition, this enzymatic sensor demonstrated better reproducibility and lifetime.

Keywords

• glucose oxidase
• manganese ferrite
• nanoparticles
• glucose sensing
• cyclic voltammetry
• amperometry