Selective identification of specific aptamers for the detection of non-typhoidal salmonellosis in an apta-impedimetric sensing format
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The authors report on an aptamer-based method for the detection of S. Typhimurium. The aptamers were identified by using a modified cell-based SELEX method (cell-SELEX) by adopting an alternating negative-positive selection strategy. Each cross-reactive population was used separately, with a focus on generating strain-specific aptamers in order to enhance selectivity. The aptamers were characterized and chemically modified with thiol groups at the 5′ end which enables covalent binding to gold nanoparticles on a screen printed carbon electrode (GNP-SPCE). The aptamer-modified GNP-SPCE was subsequently applied to impedimetric sensing of S. Typhimurium in water and food samples. Response is linear in the 10 to 105 CFU⋅mL−1 concentration range, and the limit of detection is ~10 CFU⋅mL−1. The assay can distinguish S. Typhimurium from S. Typhi and has been validated in water and spiked egg samples.
KeywordsS. Typhimurium Modified cell-SELEX Gold nanoparticles Impedimetry Aptasensor Microbial pathogen
The authors thank DBT, India (Grant No. BT/IN/FINNISH/09/CRS/2013) for providing the financial support for this project. Authors also thank Dr. Priyanka Sabherwal and Munish Shorie for the technical support, and Mr. Deepak Bhatt for confocal studies.
Compliance with ethical standards
The authors declare that there is no conflict of interest regarding the publication of this paper.
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