P43 Generation of an animal-derived-free dermal matrix, including the implementation of dermal fibroblasts

Introduction and aims Many classic three-dimensional (3D) skin models contain animal-derived materials as their dermal matrix, most commonly bovine or rat collagen I. In this pioneering project, collagen I was replaced by animal-derived-free materials including sodium alginate, fibronectin and thrombin. These materials have similar network-forming properties as collagen I and exhibit high biocompatibility, which are crucial for the functional embedding of primary fibroblasts in this dermal matrix enabling cell adhesion, proliferation and cell–cell communication. All materials were animal-derived-free with an additional focus on animal-derived-free cell culture media for the entire life cycle of the fibroblasts from their isolation to the integration into the new model system. The generation of an animal-derived-free dermal matrix is a crucial step to creating an animal-derived-free full-thickness 3D skin model. The aim of this project was to evaluate whether animal-derived-free material dermal matrix can be an effective replacement of a bovine collagen I dermal matrix. Methods The animal-derived-free materials, sodium alginate, fibronectin and thrombin matrixes (both in combinations and single material matrixes) were compared with bovine collagen I matrixes. Firstly, fabrication of matrixes was evaluated, e.g. gelation and crosslinking were applicable. The matrixes were then implemented with dermal fibroblasts. The matrixes with fibroblasts embedded were studied under SEM to assess overall structure and architecture: additional experiments were performed including immunohistochemistry (IHC), 3D viability assays and cell–cell and cell-matrix adhesion experiments. Results The results showed that the embedded fibroblasts were viable in the dermal matrixes and showed cell-to-matrix adhesion throughout the matrix. The IHC-stained dermal matrixes with fibroblasts embedded, were shown to have Ki67, collagen I and adhesion marker expression. SEM imaging of the matrixes showed the differences in morphology between matrixes. Conclusions This project analysed the effectiveness of animal-derived-free materials to create a dermal matrix compared with bovine collagen I, examining multiple factors including SEM imaging and IHC staining.