Enzymatic electrochemical biosensor for glucose detection based on biomass-derived Fe3O4/C and PEDOT:PSS modification

Abstract

Enzyme-based electrochemical biosensors allow sensitive and selective detection of blood glucose levels and enable diabetes patients personalize their treatment plans. Biocompatible, low-toxic, abundant and electroactive iron oxide (Fe3O4) nanoparticles are widely used as biosensor electrode materials. Herein, Fe3O4/Carbon (Fe3O4/C) nanocomposite was obtained through hydrothermal carbonization and successive calcination of heteroatom-rich spirulina (Arthrospira platensis,SP) biomass on Fe3O4 nanoparticles. Functionality and electrical conductivity of the Fe3O4/C nanocomposite was further enriched by a conductive poly(3,4-ethylenedioxythiophene) polystyrenesulfonate coating (Fe3O4/C/PEDOT:PSS). Glucose oxidase (GOx) was physically immobilized on the electrodes and glucose was detected by means of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. The glucose detection limits for the Fe3O4/C/GOx electrode were calculated as 0.73 mM (CV) and 1.04 mM (EIS) in the linear concentration range of 5-15 mM. The glucose detection limits for the Fe3O4/C/PEDOT:PSS/GOx electrode were calculated as 0.03 mM (CV) and 0.13 mM (EIS) in the linear concentration range of 0.5-1.5 mM. The selectivity of the biosensor was tested in the presence of ascorbic acid. Sensitive, selective, low-cost, and biocompatible electrodes provide a valuable tool in the management of diabetes.