Genosensor based on a nanostructured, platinum-modified glassy carbon electrode for Listeria detection

Abstract

In this article, we describe the development of a simple and cost-effective genosensor probe based on a glassy carbon electrode modified with platinum nanomaterials dispersed in a chitosan matrix. Further, this probe was explored for the label-free detection of Listeria monocytogenes obtained from milk samples. DNA-based interfacial interaction between target DNA and platinum nanomaterials (PtNPs) immobilized with 24 mer ssDNA was investigated using impedance spectroscopy. As-prepared nanomaterials (for electrode fabrication) were characterized by UV-vis, FT-IR, TEM and cyclic voltammetry before fabricating the impedimetric sensor platform. The interfacial interaction between PtNPs and DNA results in the increase of charge transfer resistance (R_CT) on hybridization with consecutive increasing concentrations of target DNA. This user-friendly and simple platform was used for the detection of target DNA and shows excellent response and specificity (even for 1-bp mismatch of target DNA). Also, this sensing platform was utilized for the detection of Listeria monocytogenes in real samples (milk beverage) and had a wide range of detection from 1 × 10⁻¹² M to 1 × 10⁻⁴ M. In general, our simple and user-friendly sensor probe shows potential for detection of Listeria monocytogenes in food samples with high specificity.