Anaerobic Chamber for Cell Cultivation

Personal Information

Project Members: Katie Richter and Seth Croslow

Background

Gut bacteria grow under anaerobic conditions inside the body; however, we do not have the proper equipment to effectively mimic the environment of a human gut at this time. Currently, we grow this bacteria in the incubator shaker and the plate reader, but this can only be done in an aerobic environment. Ideally, the bacteria would be grown and experimented upon in an anaerobic chamber (otherwise known as a glove box). Therefore, we would like to build our own version of a glove box to provide the necessary environment to best facilitate the growth of common types of gut bacteria for experimentation.

Construction

The construction of the anaerobic chamber will be simple and will only require a few components listed below (Note: an X represents that we currently have the item):

• Plastic tote
• Power supply (specs TBD) X?
• Arduino Uno X
• Peltier Module X
• Heat Sink X
• Transistor X
• LCD Screen X
• Rotary Potentiometer X
• Temperature Sensor X
• Foam/sealer(caulk?)
• Valves (2x)
• Estimated Cost: $50

The setup is simple, the plastic tote will be sealed using the foam and cutouts will be made for the peltier module and temperature sensor. The peltier module and fan will be used to regulate the temperature and will be attached to the side of tote. The Arduino, power supply, and LCD screen will be housed in a separate container (made via 3D printing). A simple circuit will be made to power and control all of the peripherals and software will be written using Arduino IDE.

Usage/Methodology

Once finished, the plate reader can be placed into the tote as well as some dry ice. Once the dry ice sublimates, it will displace the air within the tote which will then escape through a valve on the top of the tote. Then, nitrogen will be filled into the container from a valve in the top to remove the CO2 and thus produce the anaerobic conditions necessary. The peltier module will then be turned on and the temperature will be increased until 37℃ is reached; this temperature will then be held constant.

Sample Calculations

Amount of CO₂ Needed per Trial

• Assuming a 64 quart plastic container = ~60.6 liters
• Displace 1.5x volume to account for CO₂ loss from top = ~90 liters
• Assuming STP conditions and 1 mole of CO₂ = 22.4 L
• Moles CO₂: 90 / 22.4 = ~4 moles of dry ice
• Mass of CO₂: 4 mol * 44.01 g/mol = 180g of dry ice = .04 lbs
• Assuming price of $2/lb = ~$1 per trial

Possible Circuit Design