Aptamer-based Impedimetric Sensor for Bacterial Typing

TL;DR

This paper presents a rapid, specific, and label-free impedimetric sensor using aptamers for bacterial typing, capable of detecting Salmonella enteritidis with high sensitivity and distinguishing it from related bacteria.

Contribution

It introduces a novel aptamer-based impedimetric sensor for bacteria typing, demonstrating high specificity and rapid detection of Salmonella enteritidis.

Findings

Detects S. enteritidis down to 600 CFU/mL in 10 minutes

Successfully distinguishes S. enteritidis from other bacteria

Uses a cost-effective, label-free electrochemical platform

Abstract

The development of an aptamer-based impedimetric sensor for typing of bacteria (AIST-B) is presented. Highly specific DNA aptamers to Salmonella enteritidis were selected via Cell-SELEX technique. Twelve rounds of selection were performed; each comprises a positive selection step against S. enteritidis and a negative selection step against a mixture of related pathogens, including Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Citrobacter freundii to ensure the species-specificity of the selected aptamers. After sequencing of the pool showing the highest binding affinity to S. enteritidis, a DNA aptamer sequence of high affinity to the bacteria was integrated into an impedimetric sensor via self-assembly onto a gold nanoparticles-modified screen-printed carbon electrode (GNPs-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect S. enteritidis down to 600 CFU 1/mL (equivalent to 18 CFU in 30 \muL assay volume) in 10 minutes and distinguish it from other salmonella species, including S. typhimurium and S. choleraesuis. This report is envisaged to open a new venue for the aptamer-based typing of a variety of microorganisms using a rapid, economic, label-free electrochemical platform.