Physico-chemical modification of gelatine for the improvement of 3D printability of oxidized alginate-gelatine hydrogels towards cartilage tissue engineering

This work explored 3D printing to mimic the intrinsic hierarchical structure of natural articular cartilage. Alginate di-aldehyde- gelatine (ADA-GEL) hydrogel was used as ink to create hierarchically ordered scaffolds. In comparison to previously reported ADA-GEL compositions, we introduce a modified formulation featuring increased amounts of thermally modified gelatine. Gelatine was degraded by hydrolysis which resulted in tailorable printability characteristics further substantiated by rheological analysis. ADA (3.75 %w/v)-GEL (7.5 %w/v) with gelatine modified at 80 degrees C for 3 h could be printed in hierarchical complex structures reaching scaffold heights of over 1 cm. The hierarchical structure of the scaffolds was confirmed via mCT analysis. To examine mechanical properties as well as the suitability of the hydrogel as a proper matrix for cell seeding and encapsulation, nanoindentation was performed. Elastic moduli in the range of similar to 5 kPa were measured. Gelatine heat pre-treatment resulted in modifiable mechanical and rheological characteristics of ADA-GEL. In summary, this study demonstrates the possibility to enhance the printability of ADA-GEL hydrogels to fabricate hierarchical scaffold structures with shape stability and fidelity, without the necessity to change the initial hydrogel chemistry by the use of additives or crosslinkers, providing a valuable approach for fabrication of designed scaffolds for cartilage tissue engineering. (C) 2021 The Author(s). Published by Elsevier Ltd.

Automated summary

This study utilized 3D printing to fabricate hierarchical scaffold structures mimicking the natural articular cartilage, demonstrating the possibility to enhance the printability of ADA-GEL hydrogels for cartilage tissue engineering. The modified formulation featuring increased gelatine amounts and heat pre-treatment showed tailorable printability characteristics and modifiable mechanical properties, providing a valuable approach for designing scaffolds without the need for additives or crosslinkers.