Selective identification of specific aptamers for the detection of non-typhoidal salmonellosis in an apta-impedimetric sensing format

• Published in: Mikrochimica acta (1966) 2017-05, Vol.184 (5), p.1499-1508
• Main Authors: Pathania, Preeti, Sharma, Arunima, Kumar, Binod, Rishi, Praveen, Raman Suri, C.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Covalence; Gold; Microengineering; Nanochemistry; Nanoparticles; Nanotechnology; Original Paper; Selectivity
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-017-2098-2

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 10 5  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. Graphical abstract A modified Cell-SELEX approach for screening species specific aptamer for the impedimetric detection of non-typhoidal Salmonellosis.