Vitrification of tissue engineered pancreatic substitute

Abstract Despite significant advances, some critical issues remain for the long-term storage of an engineered pancreas. In this study we employed a tissue engineered pancreatic substitute model—insulin-secreting βTC3 cells entrapped in calcium alginate/poly-L-lysine/alginate beads—to demonstrate that a prototype vitrification method can prevent ice formation and maintain cell viability/function. The results showed that the structure of the frozen samples was distorted by ice crystals throughout the matrix. In marked contrast, the vitrified samples appeared to be free of ice. Morphologic studies demonstrated extensive fractures and vacuolation in frozen specimens while there were no fractures in vitrified TEPSs. Both vitrified and frozen constructs showed some vacuolization compared to the control samples. Frozen beads showed a significantly decreased viability compared to fresh controls and the VS55 group ( P