Team:Lethbridge HS/Hardware
Lyophilization is a very useful and underrated process as it helps freeze-dry items without disrupting its structure. This can be very useful when working with heat-sensitive materials such as proteins, microbes, pharmaceuticals, tissues and plasma. Unfortunately, they're expensive and some teams can't afford it. Our project this year includes a diagnostic system that includes a lyophilized paper strip as our diagnostic tool. We wanted to better understand the whole process of lyophilization and get more of an insight into the process so we could personalize it to our project. We built our own DIY lyophilizer using items we found around our lab. We used basic items all of which are cheap and super accessible to the public. By making this lyophilizer, we wanted to provide a way for other teams who do not have access to a lyophilizer a way to freeze-dry their products.
Lyophilization is a process in which water is removed from a product using the process of sublimation. Sublimation is the transition of products from a solid-state to a gaseous state. This can be helpful because it can protect a product from deterioration, which will make it easier to transport, or extend its shelf life ("What Is A Lyophilizer? How Does It Work? Millrock Technology, Inc."). The process of lyophilization includes three main steps: Freezing, Sublimation and Desorption. To perform this process, a vacuum must be created around a frozen product inside a vacuum chamber, then the vacuum pulls the water vapour released from the product into the second chamber, where it is condensed. Once it is done freeze-drying, the product can be taken out of the lyophilizer.
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Advantages of a Lyophilizer:
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1.Allows drying of a product without damaging its structure ("Lyophilization Of Parenteral (7/93)")
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2.Does not require large amounts of heat
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3.Increases the shelf life of a product ("Advantages Of Lyophilization For Long-Term Sample Storage")
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Disadvantages of a Lyophilizer:
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1.Requires long cycles and long periods of time
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2.Sterilization of the chamber after the cycle occurs so as to not contaminate samples
The two major components essential to the success of a lyophilizer are a vacuum chamber and a condenser. To start, we found two vacuum-sealable flasks. One of these flasks will act as the vacuum chamber that will hold the frozen sample. The other chamber will act as a condenser that will trap the vapour leaving the vacuum chamber. To Lyophilize products, we must create a vacuum around the frozen product so that it can initiate a process of sublimation. To regulate appropriate temperatures for this system to work, we placed each flask in a styrofoam icebox. The vacuum chamber will be placed in an icebox with small amounts of ice to ensure that the sample doesn’t melt during this process. However, we don’t want too much ice as that will not allow the product to sublime. To guarantee that the condenser does its job by collecting all the vapour, we placed it in an insulated closed icebox with dry ice. This should help the flask stay at very cold temperatures and condense the vapour coming into the chamber. We then used plastic tubing to connect the two chambers together, forming a path for the vapour to travel from the vacuum chamber to the condenser. Finally, we connected the condenser to the vacuum pump. By doing this, there is a vacuum created in the system which is essential as it draws the water vapour out of the sample chamber and takes it to the condenser. Once the system runs long enough, all of the moisture from the sample should have left, leaving you with a freeze-dried sample!
To test our lyophilizer we decided to set up an experiment. We chose 3 pieces of mango to test. We recorded the initial weight then placed each piece into the lyophilizer for 9 hours. The following results are shown below. As you can see, each piece of mango had decreased in weight once the Lyophilization cycle was over meaning they lost at least some water. Once it was over we still noticed that each piece still looked slightly wet meaning we may have needed to place them in a longer cycle. We also noticed that frost build-up occurred on the inside of the condenser which is a sign that some water was drawn from the mango pieces.
| Mango | Initial Weight | Final Weight | Time |
|---|---|---|---|
| Piece #1 | 0.21g | 0.15g | Start: 10:16 AM |
| Piece #2 | 0.15g | 0.10g | Finish: 6:44 PM |
| Piece #3 | 0.36g | 0.25g | Total (hours): 9hrs |
Things to consider while making your lyophilizer:
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1. In order to ensure the effectiveness of your system, it is very important to maintain a vacuum in your system until the end of the cycle.
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2. You want to have a chamber that is proportionate to the size of your sample. Having a chamber that is too big for your sample is not ideal. This is because it will be harder to maintain a constant temperature throughout the cycle.
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3. The process of lyophilization requires a long period of time. This process can take anywhere from 24 hours to 72 hours depending on the size of your sample.
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4. When choosing the tubing, be sure that it will withstand the vacuum inside.
In the future, teams may be able to use a design similar to ours for their own projects. It can be a cost-effective and optimal option for teams who can not afford a lyophilizer or simply do not have access to one. The simple design can be very helpful for high school teams like us because it is easy to understand and is extremely cost-effective! In the future, we can also use the lyophilizer on our paper strips so that we can test their effectiveness.
References
“What Is A Lyophilizer? How Does It Work? Millrock Technology, Inc.". Millrock Technology, Inc, 2019,https://www.millrocktech.com/lyosight/lyobrary/what-is-a-lyophilizer/. Accessed October 20th, 2019
"Lyophilization Of Parenteral (7/93)". U.S. Food And Drug Administration, 2019, https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/inspection-guides/lyophilization-parenteral-793.
"Advantages Of Lyophilization For Long-Term Sample Storage". Laboratory-Equipment.Com, 2019, https://www.laboratory-equipment.com/blog/advantages-of-lyophilization-for-long-term-sample-storage/.