Team:Mingdao/Applied Design

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Prototype

Not only in the lab,
we brought our design into reality

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Acid-resistant Microparticles

To make probiotics as a good food supplement, one may consider the engineered microbes need to pass through gastric acid in the digestive system. Calcium alginate nanoparticles are good carriers for delivery which are acid-resistant (pH=2) and releasing in basic environment (pH=9). The following is our protocol in the microencapsulation process.

Microencapsulation

1. Make 0.5% alginate: 0.5 g of Alginic acid sodium salt (SIGMA-ALDRICH) in 100 ml of H₂O. Heat at 50°C and cool down to ~37°C.
2. Add 1x10⁹ cells/ml of E. coli expressing GFP in the 1% alginate.
3. Make 1% CaCl₂: 1 g of Calcium chloride (SIGMA-ALDRICH) in 100 ml of H₂O
4. Use a dropper to aspirate the 1% alginate containing bacteria and drop slowly into 1% CaCl₂.
5. Incubate for 30 seconds and pick up the micro-spheroid particles carrying bacteria.

 

 

Test in Acidic and Basic Environment

1. Make solutions of pH=7, pH = 2, pH=9 to mimic esophagus stomach intestine environment, respectively.
2. Put ~30 micro-spheroid particles carrying bacteria into 100ml of each solution
3. Keep at room temperature for 4 hours
4. Take 100ul to one well of 96-well plate and measure GFP at Ex/Em=485/528nm with a BioTek microplate reader.
5. Spread 100ul onto agar plates. Grow at 37°C overnight and count the numbers of colonies.

 

 

Results

  The GFP values are higher in pH=7 and pH=9 compared to pH=2.

  1071 colonies grew on agar plates from the solution of pH=9. But there were not any colonies surviving from the solution of pH=2

The data above indicated that the micro-spheroid particles may release the microbes which survive in an environment of pH=7~9.

• Reference
• Preparation methods and applications behind alginate-based particles. Expert Opin Drug Deliv. 2017;14(6):769-782.

Simulation with a prototype

 

 

We designed a cable car-like device to simulate food (capsule) entering and passing through the human digestive system. By the environment it has to stays like mouth, stomach, intestinal tract, and how long it will stay, we ensured that our capsule will be released only in the intestinal tract rather than breaking down in unintended areas (Too early or too late). What’s more, this device is not designed only for our project. It can be used to test any other kinds of capsule easily by simply changing the substances in the liquid and the operating time of the cable car.

Design

Figure 1 Liquid container

We make Acrylic Sheet a box and a cover with holes. The container is separated into three sections── neutral(mouth), Acid(stomach), and Alkaline(intestinal tract). The holes on the cover are to avoid the liquid inside splitting out, but the size of them are designed to let a capsule get through exactly.

Figure 2 NXT LEGO track device

We chose NXT Lego to build the cable car track above because of its simplicity and creative. Put the cable car-liked device on the cover and start the program.Soaking the capsule in the liquid orderly, and decide how long we soak the capsule according to the time food stays in the Digestive tract.

Component

Figure 3 Lid of container

Figure 4 Container

User Guide

Our cable car-liked device is simple and safe for anyone to use. User only have to do is hang the capsule which waiting for detection on the transport carriage, and push the start button on the core(the orange one). Then observe the result patiently. It can show us when will capsule break down and release medicine. It can also test various pill by just adjust the solution in the container or the time the capsule soak in solution.