Wiktionary
n. (context biology English) Any substance (typically a polyhydric alcohol) that prevents cell damage on freezing
Wikipedia
A cryoprotectant is a substance used to protect biological tissue from freezing damage (i.e. that due to ice formation). Arctic and Antarctic insects, fish and amphibians create cryoprotectants ( antifreeze compounds and antifreeze proteins) in their bodies to minimize freezing damage during cold winter periods. Cryoprotectants are also used to preserve living materials in the study of biology and to preserve food products.
Usage examples of "cryoprotectant".
The first is getting the cryoprotectants, which tend to be very toxic in concentration, to every cell in the body without killing the body in the process.
The third and fourth problems are the reverse of the first two, thawing the subject safely, and getting all the cryoprotectants back out of the subject.
Once brought back to a temperature above freezing the subject needs to be deperfused to flush the cryoprotectants back out of the system, then finally warmed back up to body temperature, hopefully none the worse for the wear.