Nanoporous gold as a suitable substrate for preparation of a new sensitive electrochemical aptasensor for detection of Salmonella typhimurium

Nowadays, achievement to easy, fast, reliable and cost-effective techniques and tools is one of the most important challenges in detection of microorganisms. Salmonella typhimurium is one of the most important pathogenic bacteria that affect the human health and environmental infections. In this work we report a new, stable, biocompatible and cost-effective platform for construction of an aptasensor based on nanoporous gold (NPG) for detection of S. typhimurium. Nanoporous gold is electrochemically synthesized using Au-Cu alloy at the surface of Au/GCE. Thiol functionalized aptamer is used for effective linking to the surface of NPG/Au/GCE via self-assemble monolayers (SAMs) formation. Morphological and voltammetric characterizations of the fabricated aptasensor were performed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The purposed aptasensor is capable to detect S. typhimurium in a wide linear dynamic range 6.5 x 10(2) to 6.5 x 10(8) CFU mL(-1) with a LOQ of 6.5 x 10(1) CFU mL(-1) and LOD of 1 CFU mL(-1). The prepared aptasensor showed some significant advantages such as sensitivity, selectivity, repeatability and ability to distinguish between live and dead bacteria cells. The prepared biosensor is successfully applied for salmonella detection in real samples such as egg. (C) 2017 Elsevier B.V. All rights reserved.