“SapSense”- Development of a Field Based Biosensor towards Wheat Pathogen Detection
Wheat is cultivated in almost all the states in the United States of America, and it is the third most cultivated crop in terms of acreage, producing a yield of 60 million tons per year. In 2016, world production of wheat was 749 million tons, making it the second most-produced cereal after maize. The most common viruses that affect wheat in the United States are Wheat Spindle Streak Mosaic Virus (WSSMV), Soil-borne Wheat Mosaic Virus (SBWMV/SBV) and the Yellow Dwarf Virus (YDF)/ High Plains Virus (HPV). Viral infections in wheat often go unnoticed due to several reasons, and cause a loss in yield and consequently a loss in revenue which is estimated at an annual average of $35 million per year, in the United States. Traditional techniques to detect these pathogens are ELISA, dot blots and PCR, all of which are time consuming and/or require benchtop laboratory equipment, and are not suitable for rapid screening. This work aims to design and demonstrate proof of feasibility in designing a biosensor system for screening wheat viruses, through the development of a point of use system which uses the principles of electrochemical impedance spectroscopy to detect the presence of the infection causing virus. The novelty in the proposed work is to be able to detect the virus in a standard buffer, plant sap, removing the need for any kind of filtering and processing, and thereby having the ability to detect the virus in real-time . The biosensor works on the principles of affinity based bio-sensing with an immunoassay built on the surface of a gold electrode. Virus detection is achieved by characterizing impedance changes on the sensor surface associated with the binding of the virus to its affinity antibody probe, which is then measured by electrochemical impedance spectroscopy (EIS).