Team:NCTU Formosa/Engineering
Loading...
Research
From the research, we know that periodontal disease was proved to be related to many chronic and cardiovascular diseases. Among the pathogenic organisms of periodontal disease, Porphyromonas gingivalis is the most important bacteria that give rise to this bad condition in dogs. To tackle the problem at its roots, we put effort into finding the efficient way to reach the sterilization of Porphyromonas gingivalis first.
Finally, we chose antimicrobial peptides, LL-37 play the part of bacteria-killing. LL-37 not only can kill P. gingivalis [1], can also kill E. coli itself [2], preventing E. coli from overgrowing after entering the canine mouth.
Design
Sterilization is the key to periodontal disease. For the wet lab, we first expect the LL-37 could attain the mission. To observe the expression of DenTeeth’s biobrick, the RFP would be inserted behind the LL37. Because E. coli would kill by LL-37 peptide too, we added a composite part in the front of the LL-37 producing sequence, preventing engineered bacteria died before entering the month.
Only when the temperature is up than 37°C, the LuxR would be expressed (Fig.1 A). At this moment, if the concentration of bacteria is high, the amount of AHL would rise, binding with LuxR. The complex of AHL and LuxR will attach to the Plux (Fig.1 B), activating the expression of LL-37.
To see more detail click to design page.
For the dry part, by deriving differential equations based on our assumptions and substituting parameters from published articles, we could analyze the biological parameter of DenTeeth and predict the expression of LL-37.
Build
Gel figure
We successfully build engineering bacteria with LL-37, but the function of LL-37 killing the E. coli itself is far worse than we have imagined. If the E. coli could not exist with LL-37 in a proper proportion, the DenTeeth wouldn't attain the mission of solving the periodontal disease. Therefore, we use the prediction model to predict whether E. coli could grow and express under the effect of LL-37. To confirm the feasibility of DenTeeth.
Test
Model
Through the modeling build with substituting parameters from published articles, the growth of E. coli and P. gingivalis under the effect of LL-37 would be inhibited significantly. However, the figure also show that E. coli could still live with LL-37. Simply speaking, we successfully test the feasibility of denteeth and find that we can improve the denteeth with both biobrick design and efficiency optimization model.
Functional Test
By taking the method of dish culture and sticking up the filter, we drop the engineering bacteria on the filter in the center of the plate. Throughout the process of comparing the circle of inhibiting bacterium, we can prove that LL-37 expressing by our engineering bacteria can inhibit the growth of bacteria.
Learn
After understanding the effect of LL-37, we ensure the process of denteeth. Due to knowing the effect of LL-37, we take the quorum sensing system to make the denteeth express the LL-37 appropriately. Furthermore, the efficiency optimization model could optimize the benefit of denteeth.
Reference
- Xue Yang, Li Niu, et al.(2020)”LL-37-Induced Autophagy Contributed to the Elimination of Live Porphyromonas gingivalis Internalized in Keratinocytes”Frontiers in Cellular and Infection Microbiology 10:561761
- Xuelian Huang , Keke Zhang et al. (2017)”Effect of arginine on the growth and biofilm formation of oral bacteria”Archives of Oral Biology 82:256-262