Antibody-aptamer functionalized fibre-optic biosensor for specific detection of Listeria monocytogenes from food

Abstract

Aim: To develop antibody–aptamer functionalized fibre‐optic biosensor for specific detection of Listeria monocytogenes from food products. Methods and Results: Aptamer, a single‐stranded oligonucleotide ligand that displays affinity for the target molecule, was used in the assay to provide sensor specificity. Aptamer‐A8, specific for internalin A, an invasin protein of L. monocytogenes, was used in the fibre‐optic sensor together with antibody in a sandwich format for detection of L. monocytogenes from food. Biotinylated polyclonal anti‐Listeria antibody, P66, was immobilized on streptavidin‐coated optical waveguide surface for capturing bacteria, and Alexa Fluor 647‐conjugated A8 was used as a reporter. The biosensor was able to selectively detect pathogenic Listeria in pure culture and in mixture with other bacteria at a concentration of approx. 103 CFU ml−1. This sensor also successfully detected L. monocytogenes cells from artificially contaminated (initial inoculation of 102 CFU 25 g−1) ready‐to‐eat meat products such as sliced beef, chicken and turkey after 18 h of enrichment. Conclusion: Based on the data presented in this study, the antibody–aptamer functionalized fibre‐optic biosensor could be used as a detection tool for sensitive and specific detection of L. monocytogenes from foods. Significance and Impact of the Study: The study demonstrates feasibility and novel application of aptamer on fibre‐optic biosensor platform for the sensitive detection of L. monocytogenes from food products.

Biosensors for the analysis of microbiological and chemical contaminants in food

“…Valadez et al [53] achieved a LOD of 10 2 CFU/ml for Salmonella enterica in egg and chicken after 6 h enrichment and 1.5 h on their flow-based, optical (fluorescence), fibreoptic biosensor when utilising a fluorescently labelled secondary antibody. Ohk et al [65] described an alternative, optical (fluorescence) based, fibre-optic approach in which they used a capture antibody and a fluorescently labelled aptamer to sandwich Listeria monocytogenes with a LOD of 10 2 CFU/25 g in ready-to-eat meat samples following homogenisation in a stomacher. An enrichment period of 18 h and 4 h biosensor detection is required.…”

Total internal reflection fluorescence (TIRF) array biosensors for biothreat agents for food safety and food defense

“…An evanescent wave fiber-optic biosensor using aptamers for the capture of Listeria monocytogenes was recently described; cells could be detected directly from ready-to-eat meats or after an 18 hour enrichment step (Ohk et al, 2010). A similar system used to detect estradiol in water samples could potentially be used to determine whether foodstuffs are contaminated (Yildirim et al, 2012).…”

An Update on Aptamer-Based Multiplex System Approaches for the Detection of Common Foodborne Pathogens

“…In another SELEX-based technique, an aptamer-A8 (5′-ATCC ATGGGGCGGAGATGAGGGGGAGGAGGGCGGGTAC C C G G T T G AT-3 ′ ) s p e c i f i c f o r i n t e r n a l i n A (L. monocytogenes invasin protein) was used in the fiber optic sensor together with antibody in a sandwich format for detection of L. monocytogenes. This selected aptamer was very selective to L. monocytogenes with quantitative detection of 10 3 cfu/mL (Ohk et al 2010) which is of concern due to the use of bare aptamer. For enhanced detection, a wholebacterium SELEX strategy and fluorescence-based recognition for rapid detection of L. monocytogenes was reported.…”