EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

As cartilage tissue does not possess sufficient self-repair capacity the regeneration of cartilage defects represents a challenge for reconstructive surgery. Existing therapies include risks for patients e.g. the development of osteoarthritis. In the field of cartilage tissue engineering suitable biomaterials, cells and different scaffold fabrication techniques are combined, aiming to imitate native cartilage tissue. Additive manufacturing techniques have gained increased attention over the past decade, giving the opportunity to create 3D constructs of required complexity. However, a challenge with 3D bioprinting is to develop a bioink mimicking the structure and composition of the extracellular matrix (ECM) of native hyaline cartilage while at the same time having a high plasticity and hydration capacity. Hydrogels have earned widespread interest to meet these requirements due to their ability to form a 3D network with potential to resemble the native cartilage ECM. They provide an appropriate network for adhesion, proliferation and differentiation of cells. Alginate di-aldehyde (ADA) covalently bound to gelatin (GEL) presents a favorable material for 3D bioprinting. The crosslinking of protein-based hydrogels, such as GEL, using microbial transglutaminase (mTG) has shown promising results for tissue engineering applications. Therefore, standard ionic crosslinking using calcium chloride was supplemented with mTG for the manufacturing of ADA-GEL hydrogels. We characterized the resulting hydrogels regarding microstructure, mechanics, and degradation behavior. Human nasoseptal chondrocytes were embedded within ADA-GEL hydrogels and the influence of the mTG crosslinking was investigated. We examined the suitability of this matrix for cartilage tissue engineering. We found that neither the printing process nor the crosslinking by mTG impaired chondrocyte viability. The formation of cartilage specific ECM components, such as collagen II and cartilage proteoglycans, was shown. The results demonstrated that ADA-GEL has no cytotoxic effects on hNSCs, and offers a suitable microenvironment for cartilage ECM generation.