Hello Dear Researchers,
I am looking for a solution simply how I can avoid destroying the bacterial cellulose sample's structure by freezing. As a part of lyophilization, I should freeze the sample, however, the freezing is collapsing/corrupted its original structure of the sample. Some researches shows the usage of liquid nitrogen. Is there any other alternative ways?
Thanks in advance
The short answer is "no". It is note possible to freeze dry without freezing.
Looking at how you freeze the sample will control the ice crystal size, and effect 2 things: speed of drying - large crystals = fast drying. BUT - will be like big nails in the sample and may cause more damage. Supercooling and rapid freezing (e.g. in LN2) typically provides small powdery crystals = less risk of damage but drying typically takes longer.
You will then need good control and management of the sample before and during freeze drying. Don't store samples frozen in the freezer for a long period, during this time the ice crystals secondarily nucleate ... i.e. grow big!
All other methods of drying that I can think of will do many times more damage to the sample than freeze drying.
Thanks a lot for your answer. I agree. While doing it, I have learned that keeping in the freezer longer time is much more detrimental as you said, and much bigger ice crystals. I have not tried LN2. The samples are a bit bigger as I am not growing BC in the beaker. I saw copper plate usage with LN2. However, I am unsure about trying LN2 on my samples Rob Darrington
The quick way is to use cryogens for quick freezing, followed by vacuum drying.
Have you thought of using refractance window drying, very gentle, no freezing, very fast and low temperature..
https://www.foodonline.com/doc/refractance-window-food-drying-system-deliver-0001
Jasim Ahmed Thanks a lot for your answer and suggestion. I'll be definitely considering it together with LN2 after discussing this with my supervisor.
Bradley Wardrop Thank you very much for your answer. To be honest, I've never heard about that. Looks interesting. I'll be definitely reviewing it in detail.
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