Team:THIS-China/Hardware
Product Design
Team THIS-China’s initial goal was to design a simple and convenient reagent paper that would indicate the presence of oral bacteria, in which the procedure is similar to the procedure of a pH test using reagent papers.
Though reagent papers sounded nice and convenient, it was nearly impossible for the S.mutans bacteria to trigger our engineered gene circuit, which resulted in a failure. We had intended to create a system that was home friendly, non-professional friendly, cheap, and safe to use at home.
After in-depth designing, experimenting, and revising, we finalized with a simple 20~50ml test tube shaped like a reagent container that consists of three parts: a top section for mouthwash, a 0.02 um filter in the middle, and the E. coli located on the bottom. The filter will be connected to the wall of the container, thus causing the filter holes to be the only possible entrance/exit leading towards the E. coli section. Due to the standard size of E. coli (0.5~1.3 um), the engineered E. coli will not be able to travel through the filter (Diameter 0.02um). Thus, it guarantees the safety of the product in nonprofessional, antibacterial households. Also, to maintain the product's long-term stability, we have decided to include a Bacterial Cryopreservation Solution—a mixture that decreases the metabolism action of cells for long-term cold storage. This allows the customer to store our product in temperatures less than -20 for over a year and still be able to use it. From statistical results, our system was estimated to have a cost of around 80~100 RMB for each test tube (the engineered E. coli being negligible after mass production). We created a 3D model (see bottom) to enhance the idea of our system’s structure.
To use the product, samples of the human oral environment will first be extracted using mouthwash. The mouthwash will then be transported into the test tube, where large impurities will be filtered out and our target CSP protein will be able to interact with the engineered E. coli cells. The test tube will then be set in a warm, 37 degrees environment (a baby bottle warmer would be sufficient to maintain this constant temperature), and the results will show in 12 to 24 hours. If dental plaque is detected, a clear color change in the E. coli-mouthwash solution will be visible to the naked eye.
Figure 1: Our product's hardware.
References
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