Amperometric glucose biosensor based on glucose oxidase immobilized over chitosan nanoparticles from gladius of Uroteuthis duvauceli

Amperometric glucose biosensor was fabricated by immobilizing glucose oxidase (GOx) onto chitosan nanoparticles (CSNPs) in gold electrode. The chitosan nanoparticles were synthesized from gladius of squid, Uroteuthis duvauceli by ionic gelation process. The morphology and functional groups of CSNPs were characterized using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) respectively. The electrochemical glucose sensing properties of CSNPs based electrode (Au/CSNPs/GOx) was analyzed relatively with commercial chitosan particles utilized electrode(Au/CS/GOx). The surface morphology of bare Au, Au/CSNPs and Au/CS electrodes were observed using scanning electron microscopy (SEM). The cyclic voltammetry measurements revealed that both the electrodes exhibit high electrocatalytic ability towards glucose detection in the presence of oxygen. The developed biosensors possessed good amperometric response towards glucose with linear detectionrange from 0.001 to 1 mM with <= 2 s response time. The Au/CSNPs/GOx biosensor showed high sensitivity of 156.27 mu A mM(-1) cm(-2) with low detection limit of 1.1 mu M. The Michaelis-Menten kinetics evaluated for the electrodes displayed low value (K-m(app)= 0.625 mM) representing an excellent substrate affinity towards the enzyme. Moreover, this biosensor demonstrated better repeatability, reproducibility and stability. (C) 2015 Elsevier B.V. All rights reserved.