NANOHMICS INC — Department of Agriculture SBIR Phase II: 8.5

Description

Phase II Project Summary/AbstractThe lateral flow (LF) or immunochromatographic test strip is a staple test format in the foodsafety testing tool kit for its speed and ease of use in the field. However the sensitivity of LFassays is limited partly due to some lower antibody affinities and partly due to the visual detectionlimit of colloidal gold or colored latex particles. Cyclospora catagenesis is an important emergingwaterborne and foodborne pathogenic parasite that causes prolonged watery diarrhea and requiresvery sensitive detection due to low infective doses. There is a sensitive PCR-based confirmatorytest available for Cyclospora developed by the FDA already. However the Cyclospora PCR testand related clinical Cyclospora tests including modified Acid Fast staining of stool or tissuesamples require significant sample preparation (formalin-ethyl acetate treatment andcentrifugation to pre-concentrate oocysts) which prolongs detection and is confined to centrallaboratories. The PCR test cannot be used in the field or food processing plants at present yet thereis an immediate need and economic driver to bring fresh produce from Mexico and CentralAmerica (where Cyclospora is more prevalent) into the food supply chain for North America.Thus there is an urgent need for rapid field testing of large volumes of agricultural irrigation waterand produce swabs or rinsates to limit the spread of Cyclospora or try to virtually eliminate it fromthe entire North American continent's food supply.Therefore Nanohmics Inc. proposes to develop DNA aptamer (higher affinity surrogates forantibodies)-based fluorescent quantum dot (Qdot) LF test strips for Cyclospora oocysts or theirextracts for rapid presumptive screening of irrigation water and/or fresh produce swabs/rinsates inthe field or fresh produce packing and processing plants. Nanohmics proposes to achieve thehighest possible sensitivity in a rapid (< 15 minute) field test which can be assessed by red Qdot- aptamer conjugate tags on oocysts by visible or sensor-detected visible fluorescence versus greenCyclospora oocyst autofluorescence with a simple handheld UV mineral light or handheldfluorescence sensor. There is a previous USDA SBIR Phase II-funded precedent for thistechnology which the proposed PI (Dr. Bruno) completed and published for foodborne pathogenicbacteria in the open access journal Pathogens 3:341-355 2014 and several other journals. Inaddition Nanohmics will develop a 5 micron membrane filter or ultrafiltration fiber-based samplepreparation protocol (from the standard BAM method) to capture back flush and concentrate the8-10 micron Cyclospora oocysts from large volumes (10-100 liters) of irrigation water or freshproduce rinsates prior to filter fluorescence microscopy assessment or fluorescent LF strip testing.The broader impacts of this SBIR project resulting from Phase II development andproductization/commercialization of the system will include enhanced food and water safety forthe public to more rapidly and sensitively detect Cyclospora and other parasites or food andwaterborne bacterial and viral pathogens as well as better on-site decision making ability for foodprocessing and packing facilities. These facilities could use Nanohmics' proposed test strips toeasily and safely decide if foods can be sold or should be tested further and possibly sanitized withperoxyacetic acid or discarded. In addition aptamer-based fluorescent LF test strips can bedeveloped to detect a broad array of clinical veterinary environmental pollutant and otheranalytes. Initially food producers will be Nanohmics' main customers. However the customerbase could expand dramatically as Nanohmics moves fluorescent aptamer-LF test strip technologyinto the homeland security and clinical arenas to detect a wide array of toxic analytes.