Team:THIS-China/Design

Design

According to statistics from the WHO, dental caries are among the most prevalent oral noncommunicable diseases. They have burdened numerous countries and affected billions of people around the globe. Due to the time lag between dental plaque’s development and recognition, most people seeking for costly medical assistance are already suffering from severe symptoms such as acute pain or pulpitis. In order to alleviate this issue, we propose a method involving synthetic biology which enables the early detection of dental plaque.

We developed a detection kit consisting of oral rinse and a specially designed test tube that contains genetically engineered E.coli. This colony of bacteria is able to identify Streptococcus mutans, the major causative agent of dental plaque formation.

Detection Mechanism

The proposed project uses engineered E.coli as chassis for the identification of S.mutans, whose gene coding for polypeptide comC is induced during the quorum sensing process. The comC undergoes modifications by the comB auxiliary protein before being secreted into extracellular milieu through the ATP transporter comA in the form of mature CSP. Upon reaching a threshold concentration, CSP binds to the histidine kinase receptor comD, which is membrane associated, thus activating it by triggering autophosphorylation. Then, the CSP-comD complex transfers a phosphate group to the response regulator protein comE that subsequently activates nlmC transcription and the expression of a multi copper oxidase—CotA. The dye present will be degraded by this enzyme, therefore producing a color change observable by the naked eye.

Prevention by Using Oral Rinse

To apply our E. coli detection system to the real world, we decided, after conducting research on the current market, to create a novel product: a test tube with our engineered E. coli, which contains a top section for mouthwash, a filter, and the E.coli located at the bottom. Studies suggest that the human oral environment is able to be extracted using this method, and this method’s convenience makes detection at home possible. This, in turn, allows people to avoid unnecessary risks during the current COVID-19 pandemic.

References

[1] Bikash, Chowdhury Raihan et al. “Structure-Activity Relationships of the Competence Stimulating Peptide in Streptococcus mutans Reveal Motifs Critical for Membrane Protease SepM Recognition and ComD Receptor Activation.” ACS infectious diseases vol. 4,9 (2018): 1385-1394. doi:10.1021/acsinfecdis.8b00115

[2] Friedman, J. Y. (2011). The Role of Streptococcus Mutans in the Formation of Dental Caries: An Ecological Perspective. The Science Journal of the Lander College of Arts and Sciences, 5(1).

[3] Kaspar, Justin R, and Alejandro R Walker. “Expanding the Vocabulary of Peptide Signals in Streptococcus mutans.” Frontiers in cellular and infection microbiology vol. 9 194. 6 Jun. 2019, doi:10.3389/fcimb.2019.00194

[4] Biber, A., Lev, D., Mandelboim, M. et al. The role of mouthwash sampling in SARS-CoV-2 diagnosis. Eur J Clin Microbiol Infect Dis 40, 2199–2206 (2021). doi:10.1007/s10096-021-04320-4