Layered protein fiber scaffolds for skin tissue engineering

• Applicant: Professorin Dr. Dorothea Brüggemann
• Subject Area: Biomaterials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 504980443

Due to the rapidly aging population and increasing incidence of diabetes and obesity, the number of skin wounds has increased tremendously worldwide. Current approaches to treat skin defects bear manifold disadvantages including limited availability of viable donor cells or time-consuming in vitro expansion of harvested cells. Therefore, skin regeneration remains a major challenge in regenerative medicine that requires novel scaffold materials. When developing new skin models, it is particularly important to mimic the layered architecture of native skin with varying porosity and thickness. At the same time, skin substitutes need to support the simultaneous growth of different cell types by selectively targeting different integrins. Yet, despite extensive research in skin regeneration there is still a knowledge gap when it comes to multi-layered protein scaffolds for in vitro studies as required for skin tissue engineering. Therefore, the aim of our project is to establish layered fibrinogen-collagen scaffolds with nanofibrous architecture as new cell-free scaffolds for skin tissue engineering. Our project will be based on the key question “Are nanofibrous fibrinogen-collagen composites with layered 3D-architecture suitable scaffold materials for skin tissue engineering?”, which we will answer in three consecutive work packages (WPs). WP 1: We will establish new layered protein scaffolds by combining different self-assembly routines for fibrinogen and collagen nanofibers into a new process. An important focus will be on tailoring the thickness and porosity of individual protein layers to closely mimic the biophysical features of native skin. Finally, we will develop a detachment routine to reproducibly fabricate free-standing protein scaffolds with layered architecture. WP 2: To facilitate the application of layered protein scaffolds as skin models in a moist environment their mechanical characteristics and swelling properties need to be tailored. Moreover, to study the interaction of fibrinogen-collagen scaffolds in a co-culture setup at the air-liquid-interface (ALI) the scaffolds need to be mechanically stable when being rehydrated. Therefore, we will analyze the mechanical properties of rehydrated protein scaffolds by tensile testing in combination with studies of the swelling behavior. WP 3: Successful skin repair requires the co-cultivation of different cell types. Therefore, we will use HaCaT keratinocytes and human dermal fibroblasts to study their growth and infiltration on layered protein scaffolds at the ALI under in vitro conditions. Important parameters to evaluate different co-culture setups will be cell proliferation and migration as well as cell-specific morphology and expression of different proteins. Based on this work program, our project will introduce a new skin model for in vitro studies that will provide fundamental insights into the interaction of skin cells with layered scaffolds.

• DFG Programme: Research Grants