Effects of Freezing on Functionality and Physicochemical Properties of A 3D-Human Skin Model

Abstract

Background: Three-dimensional skin substitutes reconstructed by tissue engineering have strong potential to emulate skin conditions in vivo, although their production necessitates a relatively long period of time. Storage of cry preserved substitutes among time, using some kind of banking system, would be a conceivable solution to make their utilization more appealing for dermo pharmaceutical testing. This study evaluated the effects of freezing at -20°C over a period of 2 months on the structural and physicochemical properties of skin substitutes produced by tissue engineering. Method: Skin substitutes were produced according to the self-assembly method which is based on fibroblasts’ capacity to create their own extracellular matrix in vitro. Characterization of frozen skin substitutes was performed by percutaneous absorption analyses and attenuated total reflectance Fournier transform infrared spectroscopy (ATR-FTIR) to compare functionality and physicochemical properties of a frozen/thawed stratum corneum with a fresh counterpart. Results: Permeability analyses revealed a significant increase in the penetration profiles of benzoic acid through frozen/thawed skin substitutes although ATR-FTIR results showed no significant differences on the lipid conformation of human skin and skin substitutes after the freezing process. Conclusion: The functionality of the skin substitutes appeared affected by a freezing process nevertheless their structural integrity was preserved.