Low-Cost, Controllable Hypoxia Chamber

=Problem definition= The aim of this project is to design and construct a low-cost, controllable hypoxia chamber for stem cell research. The results from this project will be published in an open access journal.

Background
A crucial component to conducting stem cell research is maintaining a hypoxic growing environment. Stem cells naturally grow in a low-oxygen environment and simulating this environment during experiments allows researchers to more efficiently cultivate stem cells and conduct research regarding the effect of low-oxygen environments on the cells’ development. A hypoxic environment can be simulated by using cobalt chloride, but this has undesired side effects on the cells’ health. A more realistic and effective solution is to cultivate the cells in a hypoxic chamber. However, current commercial hypoxia chambers are expensive. The objective of this project is to develop a functional, simple, and low-cost hypoxia chamber for stem cell research. The results of this project will include the hypoxia chamber design and physical product as well as a published paper detailing our design and construction process. This will allow other researchers to utilize our technology and ideas.

Deliverables
The final deliverables for this project will be a functional, controllable hypoxia chamber that cost less than $1000 dollars to build. The chamber will fit inside a standard size incubator and function within the incubator environment. It will be capable of maintaining hypoxic conditions for minimum periods of 21 days, also safe for sterilization and reusable for multiple experiments. The chamber control system will be controlled through a GUI, where the user can customize the O2 and CO2 gas levels as well as monitor the current chamber conditions and save the data to a CSV file.

Specifications
Chamber specifications:
 * Must be capable of controlling oxygen levels between 1% and 21%.
 * Must be capable of maintaining carbon dioxide level at 5%.
 * Control system for chamber will have an operational voltage of 5V.
 * Chamber components must withstand temperatures of up to 50 degrees Celsius and a humidity level of 85-95%.
 * At least four 13cm x 9cm x 2.5cm well multidishes must fit inside.
 * The chamber should be easily portable.
 * When closed, it should be airtight for ease of maintaining hypoxic environment.
 * Final product should be transparent so that well multidishes are visible.
 * Total cost of chamber and manufacturing must not exceed $1000.

=Design considerations= When designing the chamber, the following must be taken into consideration:
 * Materials used must not affect culturing of stem cells.
 * Door opening must be large enough to move well multidishes in & out safely
 * Pressure must not be able to build up within chamber

=Design development= This section details the design development for the various components of our system. The information in each sub-section is presented in chronological order so that anyone can see the progression of our ideas over the course of the project.

Chamber from scratch
One initial idea we had for the chamber was custom designing a box using a modeling software. This would allow us to tailor the design of the chamber to our needs. This design would be constructed by cutting sheets of a hard plastic and using epoxy to adhere the chamber along the edges.

Pre-built chamber
Another idea we had for the design of the chamber was to purchase a pre-made container that we could modify to fit our needs. This idea is a good option as it is cheaper than buying acrylic and cutting it, and the pre-made container would be guaranteed airtight.

Control system
The control system consists of an O2 sensor, a CO2 sensor, and three gas solenoids, two of which input O2 and CO2 into the system and the other exhausts gas out of the chamber. The sensors will be mounted inside the chamber to monitor the conditions, which are sent to the microcontroller via serial communication. The solenoids are then opened, if needed, for the appropriate amount of time necessary to reach and maintain the desired chamber conditions. The system relies on a PI controller to avoid overshoot while reaching the O2 and CO2 setpoints.

User interface
=Prototypes=

Final product
=Validation=

Humidity tray volume analysis
 Volume ratio analysis: 

To determine whether or not the humidity tray we chose for our chamber is sufficient, the ratio of our chosen humidity tray volume to the chamber volume was compared to the ratio of the incubator humidity tray volume and the incubator volume. Analysis results showed that the humidity tray chosen for our chamber will supply a sufficient amount of humidity to the chamber.

=Final deliverables= The final product of this project is a functional, low-cost and simple to manufacture hypoxia chamber. It is capable of maintaining variable O2 levels of 1% to 21% and a CO2 level of 5% for extended periods of time. The chamber fits within a standard sized incubator and operates within the incubator environment. The O2%, CO2%, temperature, humidity and pressure conditions within the chamber can be monitored from a simple user interface. The UI is also where the O2 and CO2 setpoints can be customized, and the user can set a CSV file to save experiment data to.

=Team members=

=Additional Documentation=

Budget



Design Validation Plan



GitHub Repo

GitHub Repo

Project Portfolio



Presentations















Project Schedule