3 Boyutlu Yazıcı ve Mikroakışkan Cihaz Kullanılarak Çok Katlı Deri Modeli Geliştirilmesi

This study aims to develop an in vitro tri-layered (epidermis, dermis, and hypodermis) skin model by combining 3D printing and microfluidics approaches for a high-throughput drug screening system for skin penetration tests and also develop a bioink that can be printed at room temperature. Human keratinocytes (KC) were seeded on 3D printed poly-lactide-caprolactone (PLC) scaffolds for epidermis fabrication. For dermis, mesenchymal stem cells (ADSC): human dermal fibroblasts (DF) (1:3); and for hypodermis, adipocytes predifferentiated from ADSC: DF (3:1) were loaded to GelMA polymer solution solutions, 3D printed, and UV crosslinked. Air-liquid interface (ALI) culturing was used for keratinocyte stratification of the epidermis layer and characterized in vitro by E-cadherin cell adhesion markers. The stemness of ADSCs was shown by CD105 positivity. Cocultures were established and brought together in a microbioreactor for a dynamic culture setup. Cell viability in dynamic culture was similar to static culture results. The penetration assay using dexamethasone-fluorescein isothiocyanate (Dex-FITC) was performed on a tri-layered, two-layered (dermis and hypodermis), and also cell-free constructs on a skin-on-a-chip model. The epidermis layer provided drug penetration delay in 3-layered chips. Dex was shown to be taken up by cells within an hour and released for another hour. Results indicated that our microbioreactor system can be used for an advanced drug penetration assay. In the second part of the thesis, a bioink composed of methacrylated hyaluronic acid (HAMA), alginate, GelMA and IrgaCure developed and successfully printed without cooling. Prepolymer solution was ionically pre-crosslinked with calcium chloride (CaCl2), printed, photocrosslinked, then post-crosslinked with CaCl2 solution. The final hydrogel was a tunable viscoelastic interpenetrating network composed of CaCl2 crosslinked alginate and photocrosslinked HAMA-GelMA. All cell types showed good viability in the bioprints.. Keywords: Skin, 3D Printing, In Vitro Skin Model, Microfluidics Device