Cryopreservation of suspended keratinocytes with hydroxyethyl starch

The suitability of hydroxyethyl starch (HES) as a cryoprotective agent (CPA ) for suspended keratinocytes was investigated. This study was initiated du e to the need for a CPA which also allows for a subsequent vacuum drying. U nfortunately, all established CPAs for cryopreservation of keratinocytes do trot meet the demands for freeze-drying. Since I-IFS has good cryoprotecti ve and glass forming properties, it has been used successfully for both met hods in other cellular systems. In this paper, suspended keratinocytes were cryopreserved in the presence of 10% glycerol, DMSO, or HES. Cells were co oled to -70 degrees C at a rate of -3.5 C/min, and then stored in the vapou r phase above liquid nitrogen. Cell viability was judged, after rapid thawi ng and removal of the CPA, by two different assays. The comparison of ail r esults showed that HES is a promising alternative to the established CPAs f or keratinocytes.