Developing an Artificial Pancreas

Question

What is the largest problem an artificial pancreas has to deal with?

Hypothesis

My hypothesis was that the conductivity sensor on the artificial pancreas would be the largest problem because if it wasn't submerged correctly, it might not have sensed the solution.

Procedure

Supplies:

Jameco Supplies

    • Solderless Breadboard

    • 330 kΩ Resistor

    • 100 kΩ Resistor

    • Jumper Wire Kit

    • N-channel MOSFET

    • 1 MΩ Potentiometer

    • 4 Alligator Clip Test Leads

    • Battery Holder for 8 AA Batteries w/Wires

    • 8 AA Batteries

    • 24 AWG Bare Copper Wire

Amazon Supplies

    • 12 V Peristaltic Liquid Pump w/Tubing

    • Digital Scale with 0.1 g Increments

    • 100 mL Graduated Cylinder

    • pH Test Strips

Local and Home Supplies

    • Piece of Styrofoam® 4 cm × 7 cm

    • Plastic Drinking Straw

    • Scissors

    • Metric Ruler,

    • Baking Soda

    • Measuring Cup

    • 1 L Distilled White Vinegar

    • 1.2 L Distilled water

    • 4 Mixing Bowls

    • Tape

    • Permanent Marker

  • Stopwatch

Assembling the Pancreas

    1. First place the ends of the 330k Ohm resistor into holes B1 and the first left-side red bus strip.

    2. Then, place the 100k Ohm resistor into holes C1 and the third left-side blue bus strip without allowing it to touch the other resistor.

    3. Next, take a piece of jumper wire that perfectly fits the length between holes A5 and the fifth left-side blue bus strip.

    4. Afterwards, place the MOSFET into holes B5, B6, and B7, with the black side facing away from the jumper wire.

    5. Following that, take a piece of jumper wire that is nearly half the length of the breadboard and insert it into holes A7 and A25.

    6. Thereafter, insert the three pins of the potentiometer into holes B24, B25, and B26.

    7. Then, grab another jumper wire that is the same length as the first one inserted and place the new one into holes into A26 and the twenty-first left-side blue bus strip.

    8. Next, take two alligator clips and clip each one onto a metal lead of the pump.

    9. With the pump being added to the pancreas, add on the tubing to the pump (each tube was 20 cm long).

    10. Afterwards, grab two pieces of jumper wire that are both a quarter the length of the breadboard and place one end of the first wire into hole E6 and one end of the other wire into the twenty-third left-side red bus strip hole. Connect the other ends of the wires to each alligator clip.

    11. Then, take two more wires and place one end of the first one into hole E1 and one end of the other wire into hole C7. Connect the spare ends of each wire to an alligator clip.

    12. After that, take the two wires that are connected to the battery holder and insert the red wire into the twenty-fifth left-side red bus strip hole and the black wire into the twenty-fifth left-side red bus strip hole.

    13. With the battery pack connected, insert eight batteries into the battery holder.

    14. (Conductivity Sensor)

    15. Cut two pieces of copper wire that are 15 cm long each.

    16. Tightly wrap the end of each wire around a straw 4 times and 4 cm apart from each other.

    17. Next, poke the end of each wire through a piece of Styrofoam that is 7 cm by 4 cm.

    18. Make a sharp bend in each wire just above the styrofoam to keep the wires from slipping through.

  1. Finally, connect the two spare alligator clips to the end of each wire separately.

Testing

    1. After assembling the artificial pancreas, take three mixing bowls and label one Neutralized, one Vinegar, and one Baking Soda.

    2. Next, place the bowl labeled Baking Soda onto a .0 g increment scale and measure out 28.6 grams of baking soda into the bowl.

    3. Afterwards, pour 400 mL of distilled water into a measuring cup and add it to the bowl of Baking Soda (Mix Well). Measure the pH of the solution.

    4. Then, measure out 100 mL of the solution and add it to the Neutralized bowl.

    5. Pour 100 mL of distilled vinegar into the graduated cylinder and Slowly and Carefully pour that into the Neutralized bowl.

    6. Next, mix the solution and measure its pH.

    7. Pour 200 mL of distilled white vinegar into the bowl labeled Vinegar and measured its pH level.

    8. Take the two tubes of the pump and submerge them both into the Vinegar bowl.

    9. (Have a friend or parent use a stopwatch to time any problems that occur). Place the conductivity sensor into the Neutralized bowl. When the pump starts running, adjust the potentiometer to control the speed of the pump, and label which pump has the solution flowing in and which pump has the solution flowing out.

    10. Measure the pH of the Vinegar bowl.

    11. Then, remove the conductivity sensor from the Neutralized bowl and rinse it off with distilled water.

    12. Remove the inlet tube from the solution and dry it off.

    13. Afterwards, place the tube into the Baking Soda bowl and submerge the conductivity sensor in the Vinegar bowl at the same depth it was in the Neutralized bowl.

    14. Move the end of the outlet tube around in the Baking Soda bowl while holding the dry part of the tube, moving it underneath of the sensor.

    15. When the pump stops, measure the pH of the Vinegar solution and pour the remaining solution left from the Baking Soda bowl into the graduated cylinder to measure how much was leftover.

  1. Clean bowls, tubes, and graduated cylinder and repeat steps 4-17.

Data Table

Graphs

Conclusion

In conclusion, the greatest problem with the artificial pancreas was the setting on the potentiometer. For instance, the first time I tested the pancreas, the potentiometer was turned too far clockwise which prevented the pump from running because there was more resistance. The second time around, the potentiometer was turned too far counterclockwise and the pump ran much faster than it was supposed to since there wasn’t enough resistance. The second greatest problem was the wiring because some of the wires were starting to fall out of the breadboard which prevented the pump from running. From my testing, I have realized that my hypothesis was incorrect. Although the conductivity sensor could have been a slight issue, whether or not the potentiometer was set at the correct setting was the problem I encountered in my tests. An improvement in my experiment would be to repeat my testing one or two more times for an even more accurate result. Another improvement would be to mark the potentiometer to to know when it turns off and on. In addition to this experiment, I could have tested different foods using acids and bases to see how quick and efficiently the artificial pancreas neutralizes them.

Abstract

In 2014 more than nine percent of the U.S. population had diabetes and more than a quarter of these people were undiagnosed with the disease. Many scientists and doctors have tried to find a cure to prevent diabetes, but no such cure has been discovered. Other scientists have tried to construct an artificial pancreas that can produce insulin to adjust a person’s blood sugar levels. I decided to make a substitute version of an artificial pancreas that would neutralize a solution of vinegar with baking soda. I wanted to find the different problems that an artificial pancreas has to deal with. My hypothesis was that the sensor of the pancreas would be the greatest issue because if the sensor wasn’t working, the pump wouldn’t be able to start or function correctly.

The first step for my project was to construct the artificial pancreas. After I obtained all of my materials, I began to assemble my pancreas. I used a breadboard, wires, a battery pack, resistors, alligator clips, and a conductivity sensor made from Styrofoam, copper wire, and a piece of straw. The artificial pancreas would neutralize a solution of baking soda and vinegar by pumping the baking soda into the vinegar. To ensure that the solution is neutralized, I used pH test strips to determine whether the solution was an acid, a base, or neutral. After the assembling of the artificial pancreas, I was at long last ready to begin testing. Before testing, I took three mixing bowls and labeled one neutralized, one vinegar, and one baking soda. Next, I placed the bowl labeled baking soda onto a .0 g increment scale and measured out 28.6 grams of baking soda into the bowl. Afterwards, I poured 400 mL of distilled water into a measuring cup and added it to the bowl of baking soda where I mixed the solution well. Additionally, I measured the pH of the solution. Then, I measured out 100 mL of the solution and added it to the Neutralized mixing bowl. When that was added, I poured 100 mL of distilled vinegar into my graduated cylinder and carefully poured that into the neutralized mixing bowl. Thereafter, I mixed the solution and measured its pH. Afterwards, I poured 200 mL of distilled white vinegar into the bowl labeled Vinegar and measured its pH level. I took the two tubes of the pump and submerged them both into the Vinegar bowl and placed the conductivity sensor into the Neutralized bowl. When the pump started running, I used the potentiometer to control the speed of the pump. While the pump was running, I labeled which pump had the solution flowing in and which pump had the solution flowing out, and I measured the pH of the Vinegar bowl. Then, I removed the conductivity sensor from the Neutralized bowl and rinsed it off with distilled water. I removed the inlet tube from the solution and dried it off. Next, I placed the tube into the Baking Soda bowl and placed the conductivity sensor in the Vinegar bowl at the same depth it was in the Neutralized bowl. When the pump started operating, I moved the end of the outlet tube around in the bowl while holding the dry part of the tube, moving it underneath of the sensor, too. When the pump stopped, I measured the pH of the Vinegar solution and poured the remaining solution left from the Baking Soda bowl into the graduated cylinder and measured how much was leftover. I analyzed my results and decided whether the pancreas was efficient or not.

After repeating my tests, I found that it took an average of twelve minutes for the solution to be neutralized with a seven pH rating. It took thirty seconds for the pump to start running after the conductivity sensor was placed in the water. I had to adjust the potentiometer to keep the pump running. The pancreas wouldn’t operate when the potentiometer was turned clockwise too far and ran faster when the potentiometer was turned counterclockwise. I had to ensure that all of the wiring was correct and in the breadboard to keep the pump from turning off.

To conclude my experimenting, I believe that my pump was rather efficient since there were only two problems. I found that the greatest problem with my artificial pancreas was whether the potentiometer was set at the right resistance or not. When I tested the pancreas the first time around, the potentiometer had too high of a resistance which kept the pump from running. The second time around, the potentiometer didn’t have a high resistance which caused it to run too fast. The second greatest problem was the wiring because some of the wires were starting to fall out of the breadboard which prevented the pump from running. My hypothesis was incorrect because I predicted that the conductivity sensor would be the largest problem, but instead it was the setting on the potentiometer. To improve my experiment, I could have repeated the testing one or two more times to receive an even more accurate result. A follow up on this experiment would be to find certain foods that the pancreas has trouble breaking down.