Novel dermis niche equivalent based on a 3D-structure fabricated by 2-photon polymerization.

The skin as the largest human organ serves several functions, such as natural protection against internal as well as external environmental influences. Three-dimensional (3D)-tissue engineering has emerged as a promising approach for the development of functional and physiologically relevant dermis substitutes. Mimicking the topography of the dermis to develop a skin-niche model (SKN) that contains epidermal stem cells is still a challenge. This study aimed to develop a dermis equivalent featuring a physiologically relevant dermal-epidermal junction (DEJ) topography; hence, a pattern was printed using 2-photon polymerization (2PP). The depth of the invaginations can influence cell differentiation and proliferation of epidermal stem cells. The template was subsequently translated into a dermis equivalent (DE). The human neonatal dermal fibroblasts (HDFn) remodeled the DE over 14 days, resulting in reduced dimensions that remained within the physiological range. The DE contains gelatin methacrylate (GelMA) and proliferating fibroblasts that produce extracellular matrix (ECM). In a proof-of-concept, N/TERT-1 keratinocytes, as the epidermal layer, were seeded on the patterned DE to verify the adhesion and proliferation of keratinocytes on the DE. Overall, this approach enables the generation of a DE with a natural DEJ, as a more physiological skin model for future use in disease modeling, drug development, screening, and skin transplantation.