X-Message-Number: 20291 From: Date: Sat, 12 Oct 2002 10:56:20 EDT Subject: I freeze human cells every week.... --part1_70.24901e8c.2ad99214_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit > The difference between successful cryopreservation and failure lies with > size and achievable cooling rates. A single cell survives freezing if it > cools so last that the entire cell freezes at once. Such cooling must take > place at around 1000C per minute, even when using cryoprotectants. ?? We routinely freeze many different types of human cells in the Shay-Wright lab. We make a 10% DMSO/90% fetal calf serum freezing media, and then we put the cryovials in special freeze boxes full of isopropanol which SLOW DOWN the rate of cooling to roughly one degree Celsius per minute until they reach -80 Celsius. Then we throw them into the -150 for long-term storage. This is how cells have been frozen for over thirty years. What, exactly, was the source for the -1000C per minute figure? -Bill Walker --part1_70.24901e8c.2ad99214_boundary Content-Type: text/html; charset="US-ASCII" [ AUTOMATICALLY SKIPPING HTML ENCODING! ] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=20291