An electrochemical DNA biosensor based on Ni doped ZnO thin film for meningitis detection

Nickel doped zinc oxide (Ni-ZnO) thin film based matrix is used for fabricating highly stable and sensitive DNA biosensor for detecting a life-threatening disease, Meningitis. The present DNA biosensor has been fabricated after the immobilization of 23mer oligonucleotide sequence of DNA over the surface of Ni-ZnO/ITO electrode via. electrostatic interaction. Scanning electron microscopy (SEM) studies show the formation of nanostructured Ni doped ZnO thin film surface morphology which facilitates higher loading of single stranded thiolated DNA (ss th-DNA) molecules over the Ni doped ZnO matrix. The ss th-DNA/Ni-ZnO/ITO bioelectrode response studies were done using differential pulsed voltammetry (DPV) in the methylene blue (MB) mediated buffer. Linear response over wide DNA concentration (5 ng/mu l-200 ng/mu l) was obtained with a high sensitivity of 49.95 mu A/decade. The present biosensor is found to exhibit very low detection limit (5 ng/mu l) with a quick hybridization time of only 30 s. Electrochemical impedance spectroscopy (EIS) has also been used for studying the sensing response of ss th-DNA/Ni-ZnO/ITO bioelectrode. (C) 2017 Elsevier B.V. All rights reserved.