Iron oxide nanoparticles-chitosan composite based glucose biosensor.

Iron oxide (Fe(3)O(4)) nanoparticles prepared using co-precipitation method have been dispersed in chitosan (CH) solution to fabricate nanocomposite film on indium-tin oxide (ITO) glass plate. Glucose oxidase (GOx) has been immobilized onto this CH-Fe(3)O(4) nanocomposite film via physical adsorption. The size of the Fe(3)O(4) nanoparticles estimated using X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) has been found to be approximately 22 nm. The CH-Fe(3)O(4) nanocomposite film and GOx/CH-Fe(3)O(4)/ITO bioelectrode have been characterized using UV-visible and Fourier transform infrared (FTIR) spectroscopic and scanning electron microscopy (SEM) techniques, respectively. This GOx/CH-Fe(3)O(4)/ITO nanocomposite bioelectrode has response time of 5s, linearity as 10-400 mgdL(-1) of glucose, sensitivity as 9.3 microA/(mgdLcm(2)) and shelf life of about 8 weeks under refrigerated conditions. The value of Michaelis-Menten (K(m)) constant obtained as 0.141 mM indicates high affinity of immobilized GOx towards the substrate (glucose).