Special Poster Session Biofabrication
Hyaluronic acid (HA) represents a desirable material for cartilage biofabrication approaches since it is one of the major components of the cartilage extracellular matrix (ECM), where it provides not only structural and mechanical support for mesenchymal stem cells (MSCs) but also functions as a signaling molecule. This study aims to develop a flexible hydrogel platform for 3D bioprinting of MSCs by a dual-stage crosslinking process based on thiol-modified HA (HASH) and two different crosslinkers (acryl- and allyl-modified PEG).
The chemical modifications of all three components were established and optimized for gram scale production. A 3D printable formulation of HASH and Acryl-PEG, that partially crosslinks via Michael-Addition in stage 1, was identified by a custom-made screening method. Thereby, a fixed amount of HASH was combined with different amounts of Acryl-PEG in PBS, incubated at 37°C for 1h and the resulting hydrogels were analyzed with respect to their printability and properties. In stage 2, a thiol-ene reaction was conducted with Allyl-PEG under UV-light in the presence of I2959 to increase shape fidelity and biomechanical properties of the 3D bioprinted construct. Therefore, a swelling test of 3D printed hydrogels in PBS with different amounts of PEG-Allyl was performed to identify a volume stable formulation. With the final formulation, MSCs were 3D bioprinted in two stacked layers and the initial cell survival was analyzed by live-dead staining.
The study demonstrated the development of an ink formulation of HASH, Acryl-PEG and Allyl-PEG with tunable properties and a polymer content below 6 (w/v) %, suitable for 3D printing. With the developed ink it was possible to 3D bioprint MSCs with good cell survival. Ongoing work focuses on long-term survival and chondrogenic differentiation of MSCs.
This project is funded by the „Deutsche Forschungsgemeinschaft“ (DFG, German Research Foundation) project number 326998133 - TRR-225 (subproject A02).