Epidermal Basement Membrane Substitutes for Bioengineering of Human Epidermal Equivalents

Epidermal basement membrane, a tightly packed network of extracellular matrix (ECM) components, is a source of physical, chemical, and biological factors required for the structural and functional homeostasis of the epidermis. Variations within the ECM create distinct environments, which can affect the property of cells in the basal layer of the epidermis and subsequently affect keratinocyte differentiation and stratification. Very little attention has been paid to mimicking basement membrane in organotypic cultures. In this study, using parameters outlined in a consensus on the quality standard of organotypic models suitable for dermatological research, we have evaluated three basement membrane substitutes. We compared fibronectin with three complex three-dimensional matrices: Matrigel, decellularized dermal fibroblast‒produced and ‒assembled ECM, and a dry human amniotic membrane. Our results suggest that Matrigel is not a suitable substrate for human epidermal equivalent culture, whereas the two other complex three-dimensional substitutes, decellularized dermal fibroblast‒produced and ‒assembled ECM and dry human amniotic membrane, were superior to single layer fibronectin coating. Human epidermal equivalents cultured on either decellularized dermal fibroblast‒produced and ‒assembled ECM or on dry human amniotic membrane generated hemidesmosomes, whereas those on fibronectin did not. In addition, human epidermal equivalent cultured on decellularized dermal fibroblast‒produced and ‒assembled ECM and on dry human amniotic membrane can be maintained in culture 4 days longer than human epidermal equivalent cultured on fibronectin without compromising the barrier function.