Cells - Slow Freeze & Fast Thaw

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Endothelial-cell
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Cells - Slow Freeze & Fast Thaw

Post by Endothelial-cell » Tue Sep 04, 2007 9:55 am

I have a question that is during cell culture, why is that we have slowly freeze the cells and we have to be fast during thawing the cells??

Thanks!

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mith
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Post by mith » Tue Sep 04, 2007 1:42 pm

Might have to do with crystal formation
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Post by konstantin » Thu Sep 06, 2007 7:56 am

mith wrote:Might have to do with crystal formation

What crystal formation????? :)

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canalon
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Post by canalon » Thu Sep 06, 2007 2:03 pm

water->ice
Patrick

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any proof. (Ashley Montague)

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Post by konstantin » Mon Sep 10, 2007 1:26 am

canalon wrote:water->ice


and water > ice what issue can you suggest?

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mith
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Post by mith » Mon Sep 10, 2007 2:31 am

Ice- cream!
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Post by Darby » Wed Sep 12, 2007 1:36 am

As I understand it, the thaw cycle is tricky because crystals can expand among the thawing cells and rip them up.

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Post by biohazard » Sun Sep 30, 2007 12:39 pm

During freezing, water forms ice crystals that damage the cell membrane. Hence mammalian and other sensitive cells usually die no matter how you freeze them, unless you put some additives to the freezing medium - such as DMSO. The optimal rate of freezing is around 1 degree of Celsius per minute, if I recall correctly.

What comes to thawing, the situation is a little bit different. The DMSO - even though it prevents ice crystals - is toxic to cells. Therefore it is wise to thaw the cells quite quickly and then remove the DMSO. One of the main problems during thawing is not the crystal formation, but osmotic shock; too fast dilution of the cryoprservant may damage the cells. In some protocols glycerol is used instead - it is less toxic, but has bigger risk of causing osmotic shock. There are also several other issues involved, which in together make fast thawing better than slow one.

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Post by konstantin » Sun Oct 07, 2007 1:28 pm

biohazard wrote:During freezing, water forms ice crystals that damage the cell membrane. Hence mammalian and other sensitive cells usually die no matter how you freeze them, unless you put some additives to the freezing medium - such as DMSO. The optimal rate of freezing is around 1 degree of Celsius per minute, if I recall correctly.

What comes to thawing, the situation is a little bit different. The DMSO - even though it prevents ice crystals - is toxic to cells. Therefore it is wise to thaw the cells quite quickly and then remove the DMSO. One of the main problems during thawing is not the crystal formation, but osmotic shock; too fast dilution of the cryoprservant may damage the cells. In some protocols glycerol is used instead - it is less toxic, but has bigger risk of causing osmotic shock. There are also several other issues involved, which in together make fast thawing better than slow one.

good answer...:)

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