Chapter 1 2 VI Preservation and Transport

T he emerging field of tissue engineering has identified product storage as a significant obstacle for commercialization of products containing living cells. Traditionally employed methods of tissue banking utilize cryopreservation by freezing. Unfortunately, cryopreservation by freezing may result in loss of tissue function and viability by several recognized mechanisms of which ice formation is the most significant. An alternative to freezing is cryopreservation by vitrification. Vitrification is the solidification of a liquid without crystallization. The basic principals of vitrification and progress in application of vitrification to tissue preservation are reviewed with emphasis on recent successes in preservation of cardiovascular tissues and cartilage. For the future, heat transfer issues during cooling and warming and minimization of devitrification and ice growth by recrystallization during rewarming appear to be the primary hurdles for scaling up from relatively small cartilage specimens and cardiovascular grafts to larger tissues and organs.