Abstract
Preliminary studies aimed at improving the sensitivity of foodborne pathogen detection via lateral flow (LF) test strips by use of high affinity DNA aptamers for capture and reporter functions when coupled to red-emitting quantum dots (Qdot 655) are reported. A variety of DNA aptamers developed against Escherichia coli, Listeria monocytogenes, and Salmonella enterica were paired in capture and reporter combinations to determine which yielded the strongest detection of their cognate bacteria using a colloidal gold screening system. Several promising sandwich combinations were identified for each of the three bacterial LF strip systems. The best E. coli aptamer-LF system was further studied and yielded a visible limit of detection (LOD) of ~3,000 E. coli 8739 and ~6,000 E. coli O157:H7 in buffer. These LODs were reduced to ~300–600 bacterial cells per test respectively by switching to a Qdot 655 aptamer-LF system. Novel aspects of these assays such as the use of high levels of detergents to avoid quantum dot agglutination and enhance migration in analytical membranes, identification of optimal analytical membrane types, UV-immobilization of capture aptamers, and novel dual biotin/digoxigenin-end labeled aptamer streptavidin-colloidal gold or -Qdot 655 conjugates plus anti-digoxigenin antibody control lines are also discussed. In general, this work provides proof-of-principle for highly sensitive aptamer-Qdot LF strip assays for rapid foodborne pathogen detection.
Highlights
The popularity of lateral flow (LF) or immunochromatographic (IC) test strips especially for common tests such as pregnancy, drugs of abuse, and food safety assessments is undeniable and driven by their ease of use, speed and relative accuracy of these simple and inexpensive disposable devices.in general, standard colloidal gold or latex particle immuno-LF test strip sensitivity is limited to approximately 2,000 pathogenic E. coli cells per milliliter [1,2], but the food safety testing industry demands zero tolerance of foodborne pathogens
The simple use of several extant and independently validated foodborne pathogen aptamers [10,24] in LF test strips are illustrated and in the case of general E. coli detection, a comparison is made between colloidal gold and quantum dots (Qdots) versions of a preliminary LF assay at its approximate limit of detection (LOD)
Preliminary results presented in this report, reveal that it is possible to develop sensitive aptamer-based LF test strips for foodborne pathogen detection which rival antibody-based LF
Summary
The popularity of lateral flow (LF) or immunochromatographic (IC) test strips especially for common tests such as pregnancy, drugs of abuse, and food safety assessments is undeniable and driven by their ease of use, speed and relative accuracy of these simple and inexpensive disposable devices. In general, standard colloidal gold or latex particle immuno-LF test strip sensitivity is limited to approximately 2,000 pathogenic E. coli cells per milliliter [1,2], but the food safety testing industry demands zero tolerance of foodborne pathogens (i.e., no detectable pathogens). The simple use of several extant and independently validated foodborne pathogen aptamers [10,24] in LF test strips are illustrated and in the case of general E. coli detection, a comparison is made between colloidal gold and Qdot versions of a preliminary LF assay at its approximate limit of detection (LOD)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
