HRP modified pulse laser ablated ZnO nanostructure for H2O2 sensing
Amit Srivastava, Naresh Kumar
Volume 1, Issue 2, Page 165-170, Year 2016 | DOI: 10.5185/amp.2016/209
Keywords: ZnO, pulsed laser ablation/deposition (PLA/PLD), HRP, H 2 O 2 , biosensor.
Abstract: Biosensor for the detection of hydrogen peroxide (H 2 O 2 ) has been prepared by immobilizing horseradish peroxidase (HRP) enzyme using physical adsorption technique on zinc oxide (ZnO) nanostructures. The (002) oriented ZnO nanostructures as confirmed by X-ray diffraction, were successfully grown on indium tin oxide (ITO) coated glass substrate by pulsed laser ablation (PLA) without using any catalyst. The Nafion solution was added onto HRP/ ZnO/ ITO bio-electrode to form a tight membrane on the surface before carrying out bio-sensing measurements by electrochemical analyzer. The electrochemical studies reveal that the prepared bio-electrode HRP/ZnO/ITO is highly sensitive to the detection of H 2 O 2 over a wide range of concentration with a linear range from 2.5 μM to 100 μM with the limit of detection 0.2 μM and sensitivity of 0.034 μA/ μM cm 2 . The higher sensitivity attributed to larger surface area of ZnO nanostructure for effective loading of HRP besides its high electron communication capability. A relatively low value of the enzyme’s kinetic parameter (Michaelis-Menten constant, K m ) of 0.166 μM indicates enhanced enzyme affinity of HRP to H 2 O 2 . The reported biosensor may be useful for various applications in bio- sensing, clinical, food and beverage industry. Copyright © 2016 VBRI Press.