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Title: Label-free detection of salmonella typhimurium with ssDNA aptamers

item Park, Bosoon
item WANG, BIN - University Of Georgia
item LOU, ZHICHAO - University Of Georgia
item XU, BINGQIAN - University Of Georgia
item KWON, YONGKUK - Animal, Plant And Fisheries Quarantine And Inspection Agency (QIA)

Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/26/2015
Publication Date: 3/22/2015
Citation: Park, B., Wang, B., Lou, Z., Xu, B., Kwon, Y. 2015. Label-free detection of salmonella typhimurium with ssDNA aptamers. American Chemical Society Abstracts [abstract].

Interpretive Summary: none

Technical Abstract: Foodborne pathogen Salmonella enterica is one of the major causes of gastrointestinal infections in human and animals. Conventional detection methods are time consuming and not effective enough under emergency circumstances to control outbreaks immediately. Therefore, biosensors that can detect Salmonella rapidly with high sensitivity and specificity are needed for the modern food industry. Label-free detection methods can reduce pre-treatments of samples and realize fast and sensitive detection. Since aptamers have proved to be low-cost and stable binding reagents, aptamers have been integrated into various detection platforms for label-free detection methods. In this research two techniques were used for label-free detection of Salmonella serotypes. Atomic force microscopy (AFM) has the ability to detect single bacterium in samples, which provide highest sensitivity and the useful information for bacteria surface properties in terms of binding with anti-Salmonella aptamers. AFM dynamic force spectroscopy (DFS) was used to measure single-molecule interactions between aptamer and Salmonella surface protein in buffer solution, which maintains the physiochemical activity of Salmonella. In order to develop the biosensor for field detection, bulk solution platform surface plasmon resonance (SPR) was used as another label-free technique for fast detection of Salmonella. Both AFM and SPR detection required special surface modification with aptamers to capture the Salmonella bacteria, so that surface modification and bacteria deposition protocols have been developed. Moreover, the interactions measured in SPR and AFM were compared to study the influence of microscopic environments for the bacteria detection. The results of this study will facilitate further development of label-free biosensor for the detection of various pathogens and toxins in food matrices.