Preservation of Cell Cultures by Freezing in Liquid Nitrogen Vapor.

Abstract

Summary Nine continuous, 2 diploid and one primary cell line were successfully preserved by freezing in liquid nitrogen vapor at cooling rates of 1.4°C/min to 43°C/min, but poor survival was observed when cells were frozen by immersion directly in liquid nitrogen. The cells were frozen directly in a liquid nitrogen refrigerator by placing the ampuls at different distances below the lip, demonstrating that elaborate and expensive cell preserving equipment is not required. The plating efficiency technique was shown to be the most sensitive indicator of cell damage.