Presentation Title

Detection of Salmonella enterica Contamination in Spinach Using a DNA-based Biosensor Detection System

Faculty Mentor

Dr. Sylvia A. Vetrone

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

HARBESON 9

Session

POSTER 2

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Our developed DNA-based biosensor, which utilizes gold nanoparticles (AuNPs) for signal amplification and magnetic nanoparticles (MNPs) for easy and clean separation from samples, has been shown to detect non-PCR amplified genomic DNA targets (DNAt) from bacterial pathogens. While this detection system can provide detection within a five-hour window within liquid food matrices, it needs to be determined how well it will detect pathogenic DNA within solid food matrices. Therefore, in this study genomic DNA was extracted from spinach spiked with Salmonella enterica, E. coli (non-specific negative control), a mixture of Salmonella and E. coli, or just water (negative control) using Trizol® reagent. Genomic DNA targets (DNAt) from samples at 3ng/mL, 1ng/mL, and 0.125ng/mL were detected using the biosensor: hybridizing the DNAt into a sandwich-like structure consisting of MNPs/DNAt/AuNPs, which were then placed onto screen-printed carbon electrodes to detect the voltammetric peaks of gold using differential pulse voltammetry. Our results indicate that the biosensor is able to detect only the specified pathogenic DNAt, Salmonella enterica, down to the lower limits of the DNAt concentration of 0.125/mL (p=0.05). These findings suggest that this detection system works well with samples isolated from semi-viscous food matrices.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Detection of Salmonella enterica Contamination in Spinach Using a DNA-based Biosensor Detection System

HARBESON 9

Our developed DNA-based biosensor, which utilizes gold nanoparticles (AuNPs) for signal amplification and magnetic nanoparticles (MNPs) for easy and clean separation from samples, has been shown to detect non-PCR amplified genomic DNA targets (DNAt) from bacterial pathogens. While this detection system can provide detection within a five-hour window within liquid food matrices, it needs to be determined how well it will detect pathogenic DNA within solid food matrices. Therefore, in this study genomic DNA was extracted from spinach spiked with Salmonella enterica, E. coli (non-specific negative control), a mixture of Salmonella and E. coli, or just water (negative control) using Trizol® reagent. Genomic DNA targets (DNAt) from samples at 3ng/mL, 1ng/mL, and 0.125ng/mL were detected using the biosensor: hybridizing the DNAt into a sandwich-like structure consisting of MNPs/DNAt/AuNPs, which were then placed onto screen-printed carbon electrodes to detect the voltammetric peaks of gold using differential pulse voltammetry. Our results indicate that the biosensor is able to detect only the specified pathogenic DNAt, Salmonella enterica, down to the lower limits of the DNAt concentration of 0.125/mL (p=0.05). These findings suggest that this detection system works well with samples isolated from semi-viscous food matrices.