The skin is our primary interface towards the world, serving both as one of our main communication channels as well as being one of the most important protective barriers towards our surroundings. Skin care products, topological drugs and medical treatments are all in need of enhanced testing procedures that, in an ethical agenda, can increase the transability from in vitro testing to in vivo usage of products. With tissue engineering and 3D bioprinting more representative in vitro models can be constructed, providing the possibility to limit the usage of animal models while increasing the physical relevance of the testing models.
The aim of the following project was to develop a full thickness skin tissue model using the technique of 3D bioprinting. The study consisted of three parts; designing a model based on literature, bioprint different models of the design and analyze the models to evaluate which one that resembles the native skin the most.
• Two Bioinks: CELLINK-FIBRIN® & CELLINK-RGD®
• Two Concentrations of Compound X: High X or Low X
• Epidermis: 1 layer high concentration of keratinocytes (HEK)
• Papillary Dermis: 2 layers high concentration of fibroblasts (HDF)
• Reticular Dermis: 3 layers low concentration of fibroblasts
• Skin tissue model has good viability over 14 days, > 75%
• Higher cell count and better morphology of fibroblasts when
co-cultured with keratinocytes
• CELLINK-RGD® results in higher cell count for keratinocytes,
CELLINK-FIBRIN® more prominent viability
• CELLINK-FIBRIN® results in increased Collagen type I
production from days 7-14, green box
• High X results in less expression of KRT10 and Collagen type I
• Low X results in higher expression of KRT10, red boxes
= Low addition of X has a positive effect on ECM modulation
In this study it was shown that a full thickness skin tissue model with good viability over 14 days could be constructed with CELLINKs bioinks. In CELLINK-RGD® keratinocyte activity was maintained for the whole study. In CELLINK-FIBRIN® better morphology of fibroblasts was obtained, as well as increased collagen type I production from day 7 to day 14 with no or low addition of compound X. Indicating that CELLINK-RGD® and CELLINK-FIBRIN® provides a suitable 3D environment for construction of skin tissue models.