An impedimetric biosensor based on electrophoretically assembled ZnO nanorods and carboxylated graphene nanoflakes on an indium tin oxide electrode for detection of the DNA of Escherichia coli O157:H7

Mikrochim Acta. 2019 Dec 3;187(1):1. doi: 10.1007/s00604-019-3921-8.

Abstract

Aminopropyltrimethoxysilane (APTMS)-functionalized zinc oxide (ZnO) nanorods and carboxylated graphene nanoflakes (c-GNF) were used in a composite that was electrophoretically deposited on an indium tin oxide (ITO) coated glass substrate. The modified ITO electrodes were characterized using various microscopic and spectroscopic techniques which confirm the deposition of the APTMS-ZnO/c-GNF composite. The electrodes have been used for the covalent immobilization of an Escherichia coli O157:H7 (E. coli)-specific DNA prob. Impedimetric studies revealed that the gene sensor displays linear response in a wide range of target DNA concentration (10-16 M to 10-6 M) with a detection limit of 0.1 fM. The studies on the cross-reactivity to other water-borne pathogens show that the bioelectrode is highly specific. Graphical abstractSchematic illustration for fabrication of nucleic acid biosensor for E. coli DNA detection using an ITO electrode modified with siloxane-functionalized zinc oxide (ZnO) nanorods and carboxylated graphene nanoflakes (c-GNFs).

Keywords: Biosensor; Electrophoretic deposition; Escherichia coli; Graphene nanoflakes; Zinc oxide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques / instrumentation
  • Biosensing Techniques / methods*
  • Carboxylic Acids / chemistry
  • DNA, Bacterial / analysis*
  • Electric Impedance
  • Electrodes
  • Electrophoresis
  • Escherichia coli O157 / genetics*
  • Graphite / chemistry*
  • Limit of Detection
  • Nanotubes / chemistry*
  • Tin Compounds / chemistry*
  • Zinc Oxide / chemistry*

Substances

  • Carboxylic Acids
  • DNA, Bacterial
  • Tin Compounds
  • indium tin oxide
  • Graphite
  • Zinc Oxide