An Aptamer-Quantum Dot-Based Lateral Flow Test Strip for Cyclospora Detection

The lateral flow (LF) or immunochromatographic test strip is a staple test format in thefood safety testing arsenal.However the sensitivity of LF assays is limited partly due toantibody affinity and partly due to the visual detection limit of colloidal gold or coloredlatex particles. Cyclospora is an important water and foodborne parasite that requiresvery sensitive detection. There is a PCR-based confirmatory test available for Cyclospora.However it requires significant sample preparation and is confined to laboratories. ThePCR test cannot be used in the field or food processing plants. Therefore NanohmicsInc. proposes to develop DNA aptamer (higher affinity surrogates for antibodies)-basedfluorescent quantum dot (Qdot) LF test strips for Cyclospora oocysts or their extracts forrapid presumptive screening of fresh produce in the field or processing plants. Nanohmicsproposes to achieve the highest possible sensitivity in a rapid (5-10 minute) field testwhich can be assessed by fluorescence visually with a simple handheld UV mineral light.There is a USDA SBIR Phase II-funded precedent for this technology which the proposedPI completed and published for foodborne pathogenic bacteria in the open access journalPathogens 3:341-355 2014 and several other journals. In addition Nanohmics willdevelop a 5 micron filter-based sample preparation protocol to capture and concentrateto 8-10 micron Cyclospora oocysts from fresh produce rinsates prior to LF testing.The broader impacts of this SBIR project will include enhanced food and water safety forthe public as well as better on-site decision making ability for food processing and packingfacilities. These facilities could use Nanohmics' proposed test strips to easily and safelydecide if foods can be sold or should be tested further and discarded. In additionaptamer-based fluorescent LF test strips can be developed to detect a broad array ofclinical veterinary environmental pollutant and other analytes. Initially food processorswill be Nanohmics' main customers. However the customer base could expanddramatically as Nanohmics moves fluorescent aptamer-LF test strip technology into thehomeland security and medical arenas to detect chemical and biological terrorist threatagents infectious diseases in hospitals and patient wounds and contaminated rawmaterials in pharmaceutical production facilities among others sectors.