Interaction of preservation methods and radiation sterilization in human skin processing, with particular insight on the impact of the final water content and collagen disruption. Part I: process validation, water activity and collagen changes in tissues cryopreserved or processed using 50, 85 or 98% glycerol solutions.

Current regulatory requirements demand an in-depth understanding and validation of protocols used in tissue banking. The aim of this work was to characterize the quality of split thickness skin allografts cryopreserved or manufactured using highly concentrated solutions of glycerol (50, 85 or 98%), where tissue water activity (aw), histology and birefringence changes were chosen as parameters. Consistent aw outcomes validated the proposed processing protocols. While no significant changes in tissue quality were observed under bright-field microscopy or in collagen birefringence, in-process findings can be harnessed to fine-tune and optimize manufacturing outcomes in particular when further radiation sterilization is considered. Furthermore, exposing the tissues to 85% glycerol seems to derive the most efficient outcomes as far as aw and control of microbiological growth.