The purpose of my project is to design a low-cost, rapid diagnostic to detect the presence of the fungus Batrachochytrium dendrobatidis, which is threatening to wipe out many species of amphibians around the world. The current procedure involves transporting test samples to a laboratory and performing a DNA amplification and gel electrophoresis. While this is going on, the test amphibian needs to be quarantined and released after the diagnosis is made. This method requires a highly specialized laboratory, takes several hours to diagnose, and requires a scientist with technical training to diagnose and analyze each sample.
The design criteria for my project are to bio-ethically develop a portable diagnostic that will provide a rapid, visual, and accurate indication of the presence of the fungal pathogen. The diagnostic should be significantly cheaper than the best-in-class diagnostic (Polymerase Chain Reaction) and should not require any specialized skills to operate it. This test should be non-invasive, should not harm the amphibian, and should only require a skin swab.
My approach was to develop a lateral flow assay (test strips) by engineering a protein that has a high binding affinity to the pathogenic proteins secreted by the fungus via the Ribosome Display method. As all of the fungal proteins proved to be bactericidal, I was unable to produce any usable bacteria colonies to grow the fungal protein, so to test my concept, I used the Green Fluorescent Protein as a target protein and validated that the lateral flow assay worked by using Dot Blot assay and Pull Assay to mimic it.
My design is successful because it proved the concept that a protein can be engineered and mounted on a portable lateral flow assay to visually and accurately detect the presence of the fungal pathogen. It meets all the other design criteria. The PCR method costs around ~ $200 including the labor cost of a researcher, versus the cost of my diagnostic which is less than $0.25. It provides rapid results (a couple of minutes) vs days. It does not need any specialized lab skills. The diagnostic simply requires an in-field skin swab that is placed on the test strip and the results appear visually. The diagnostic conforms to bio-ethical standards because it is non-invasive and does not require removing the amphibian from the environment. Additionally, the method to produce the test strips does not involve the use of any animals as in the production of antibodies. As such this bioengineering project, which I started in 9th grade and have been working on for two years now at BioCurious, a local community lab in Sunnyvale, California, would be an impactful tool for both the researchers and conservationists working to stem the spread of this deadly fungus. In addition, the results show that lateral flow assays developed via ribosome display technique can be used to rapidly detect and thereby control even other types of epidemics protecting the biodiversity of ecosystems before they can spread.