Team:HZAU-China/Implementation
Implementation
Overview
According to our experimental results, Tooth Fairy will focus on the health of our teeth in real time and make corresponding responses like a real guardian fairy.
In order to put our Tooth Fairy into practical use, we have produced four matching products. It includes: a "Teeth braces" to accommodate the Tooth Fairy, M9 agaroses medium and freeze-drying bacterial powder to easily use, a "Box" to active fluorescent protein, as well as an "App" to determine and report teeth bacterial infection situation based on color. These four products will encompass a complete set of usage processes.
Teeth braces
Our "Teeth braces" can completely wrap the user's teeth, and a cavity is designed on the occlusal surface of the braces for adding engineered bacteria (Figure 1).
Figure 1. A Teeth braces in early generation. "Teeth braces" in this picture is handmade. In the future we will use the below process to produce braces. B Schematic of cavity.
Medium & bacterial powder
In future use, the products will also include M9 agaroses medium and freeze-drying bacterial powder (Figure 2) protocol see protocol page https://2020.igem.org/Team:HZAU-China/Protocol. When using the braces, users should add them into braces.
Figure 2. The M9 agaroses medium and freeze-drying bacterial powder. Due to the limited experimental time the M9 agaroses medium and freeze-drying bacterial powder are just conceptual products.
Box
In order to activate the fluorescence of fluorescent proteins, we designed the hardware "Box" (Figure 3), which has a built-in excitation light for activating fluorescent proteins.
App
After activating the fluorescent proteins and taking a photo, users only need to import their photos into the "App", the "App" can automatically identify the fluorescent color, and report the condition of bacterial infection to users (Figure 4).
Safety of implementation
Considering the situation of the project in practical implementation, we also adopted some other methods to enhance the safety of the engineered bacteria. The chassis we use is a widely recognized probiotic, Escherichia coli Nissle 1917, which poses no harm to humans or the environment. Besides, we have designed a suicide switch to prevent horizontal gene transfer that would occur when engineered bacteria escape from the treatment device in actual implementation. The interior of the device will be set to an environment rich in ferrous iron. When the engineered bacteria leave the treatment device and enter the oral cavity, gastrointestinal tract or natural environment, the decreased concentration of ferrous ions will cause the expression of toxin, then kill the engineered bacteria. Additionally, in terms of the choice of safe materials, we adopted TPU (Thermoplastic polyurethanes) material, it has the excellent properties of high tension, high strength, toughness, resistance to aging properties, and harmlessness to the human body.
Usage process
Before users go to bed, they can add M9 agaroses medium and freeze-drying bacterial powder into the "Teeth braces", and then go to bed with the braces. When the users wake up the next day, they can take off their braces, put them into the "Box" and then open the switch to active fluorescent proteins, which were produced by the Tooth Fairy. Finally, users can take photos of the braces in the "Box" through the hole of lid and import the photos into the "App" for analyzing. The "App" will report the condition of teeth bacterial infection.
Product positioning
Tooth Fairy solves mild enamel damages and treats early S. mutans infection at molecular level by using self-assembled LRAP and S. mutans-specific ClyR. The newly formed enamel has the same arrangement structure of hydroxyapatite as the original enamel, which can restore the enamel properties to the maximum extent. And because of the specificity of ClyR, the disorder of oral flora caused by broad-spectrum sterilization will not appear.
Overall, Tooth Fairy is a health care product that prevents further enamel damages, but still can’t replace the role of doctors. She can repair the enamel when it is slightly damaged and remind the user to see a doctor when the condition is serious by adding the Detection & Report module.
Due to the use of a variety of synthetic biology methods in the project, it has higher repair efficiency and cost-effectiveness than similar products.
Future work
Project in the real world
In real production process, we will first conduct a 3D scan of users' teeth. After importing the data into 3D software, we will enlarge the model data of the occlusal surface, so that the braces can be made to cover users' teeth and form a cavity. The data of non-occlusal surfaces will remain unchanged to ensure the braces fit users' non-occlusal surface and prevent the fall of it. The thickness of the braces we designed is about 0.5mm to 0.75mm, so we plan to use UV-curing 3D printers to meet this standard.
Before the public use our products, they need to come to our company for 3D scanning and make the braces that fit their teeth alignment. After the braces are made, the users will receive the couriers of products and use them.
Challenges
Because the bacteria used in the product, some users might mind the way of treatment. We need to popularize the advantages and safety of bioremediation through a series of Human practices, so as to change the attitude of them towards the product.
Most people choose to treat diseases only when they have symptoms. The early symptoms of dental diseases are mild and difficult to detect. When the disease develops to a later stage, our products can't be used for treatment. So, we need to change that concept. We plan to position the product as a health care product to motivate users to use it in their daily lives.
Although bioremediation has the advantage of restoring the enamel structure over existing methods of material filling, it takes a lot of time. Therefore, we set the use time of the product to sleep time to avoid consuming a lot of users' time.
