Study of ITO Glass Electrode Modified with Iron Oxide Nanoparticles and Nafion for Glucose Biosensor Application

AbstractIn this study, we report the fabrication of the indium tin oxide (ITO) glass electrode modified with iron oxide nanoparticles (IONPs) and nafion for glucose biosensor applications. The IONPs was synthesized using the precipitation method and functionalized with citric acid (CA) to provide hydrophilic surface and functional group for glucose oxidase (GOx) enzyme immobilization. The structural and morphological studies of CA-IONPs were characterized using X-ray diffractometer (XRD) and transmission electron microscope (TEM). The size of the IONPs measured from TEM image was ∼17nm. The bioelectrode designated as Nafion/GOx/CA-IONPs/ITO was developed by drop casting of the CA-IONPs, GOx and nafion on the ITO glass. The Nafion/GOx/CA-IONPs/ITO bioelectrode showed good electrochemical performance for glucose detection. The functionalized CA-IONPs acted as the catalyst and help to improve the electron transfer rate between GOx and ITO electrode. In addition, thin nafion film was coated on the electrode to prevent interference and improve chemical stability. The Nafion/GOx/CA-IONPs/ITO bioelectrode showed high sensitivity of 70.1μAmM-1cm-2 for the linear range of 1.0-8.0mM glucose concentrations

Development Of Working Electrode Modified By Iron Oxide Nanoparticles For Glucose Biosensor Applications

Glucose biosensor that is capable to provide wide linearity of detection, high sensitivity, and low limit of detection is important in clinical diagnosis. This has motivated the research into development of a better glucose biosensor. In this study, iron oxide nanoparticles (IONPs) were synthesized using the precipitation method and surface functionalized with varying citric acid (CA) concentration (0.10, 0.25, 0.50, and 0.70 g/ml) to produce stable colloidal IONPs in water. The effect of varying CA concentration on the crystallinity and morphology, of the IONPs–CA in water were studied using X-ray diffraction (XRD) and transmission electron microscope (TEM). From the XRD patterns, high crystallinity of spinel cubic lattice of maghemite (γ- Fe2O3) was obtained, while observation using transmission electron microscopy (TEM) showed particle size was in the range of 17–22 nm. The optimum CA concentration to functionalize IONPs–CA forming stable colloidal IONPs in water and exhibited excellent electrochemical performance was 0.25 g/ml. The stable colloidal IONPs–0.25 CA in water was then applied for fabrication of enzymatic and nonenzymatic glucose biosensor by modification of working electrode using drop casting method. In enzymatic glucose biosensor, the indium tin oxide (ITO) electrode and screen printed carbon electrode (SPCE) were modified with IONPs–0.25 CA, glucose oxidase (GOx) enzymes and Nafion layer. As for non-enzymatic glucose biosensor, the SPCE electrode was modified with IONPs–0.25 CA and Nafion layer. The optimization parameters of enzymatic and non-enzymatic glucose biosensors performance were conducted, such as effect of IONPs concentration, effect of GOx enzyme loading concentration, effect of working potential, effect of buffer solution pH and effect of operating temperature. The sensing performance of the developed enzymatic and non-enzymatic glucose biosensor exhibit excellent glucose detection performance with sensitivity of Nafion/GOx/IONPs–0.25 CA/ITO (941 μAmM-1cm-2 and limit of detection of 0.10 μM), Nafion/GOx/IONPs–0.25 CA/SPCE (164 μAmM- 1cm-2 and limit of detection of 14 μM), and 5Nafion/IONPs–0.25 CA/SPCE (2802 μAmM-1cm-2 and limit of detection 0.60 μM). The wide linearity of detection, high sensitivity and low limit of detection of enzymatic and non-enzymatic glucose biosensors were successfully developed based on modification of working electrode with IONPs–0.25

Characterization Copper (II) Chloride Modified Montmorillonite filled PLA Nanocomposites

The thermal behaviour of polymer layered silicate nanocomposite were characterised to compare the improvement of the nanocomposite with the pristine polymer. It is known that pristine polymers have some weakness in its thermal properties especially biodegradable polymers. The approach of making the nanocomposite out of modified layered silicate and biodegradable polymer is to enhance the thermal behaviour of the biodegradable polymer. The nanocomposites were produced by solution method technique using dichloromethane as a solvent and the two types of nanoclay were used. One was modified with transition metal ion and another type of nanoclay is pristine nanoclay. Wide angle X-ray diffraction (XRD) was used to characterise the structure of the nanoclay after the modification and the type of nanocomposite obtained. Melting temperature and degradation temperature of the nanocomposite were obtained by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. Decrease in both thermal degradation temperature and melting temperature of the nanocomposites were observed