Evaluation of different hydrogels (PEGDA, CSMA, HSMA, Fibrin) for 3D-Bone-Tissue Engineering

Objectives Bone cell differentiation from mesenchymal stem cells (MSCs) takes 3-4 weeks in 2D-cell culture. For transfer of the associated methodology to 3D-cell culture a biocompatible support material is necessary. Biocompatible hydrogels have been widely used as support materials for cells in tissue engineering. They can support or inhibit cell migration, differentiation and proliferation as well as oxygen or nutrient diffusion. Hydrogel composition, handling and cell interaction are therefore important factors for 3D tissue engineering, especially for long-term culture. The intent of this study to evaluate different hydrogels for long-term culture of MSCs. We aimed to determine, what is the impact of polymerization technique and hydrogel architecture?

Methods 3D cell culture We analyzed biological based hydrogel systems (e.g. Fibrin) and chemical modified polymers (e.g. PEGDA, CSMA, HAMA) as extracellular matrix for MSCs and compared their handling experience, chemical characteristics and biological effects (e.g. cell morphology). For 3D cell culture, we used a self-designed bioreactor made from a combination of 3D-printing and injection molding approaches. Bioreactors and molds were constructed using open source software “blender” and printed on an Ultimaker 3 platform. PLA was used as print material since it is known for excellent biocompatibility. The reactor was connected to a perfusion system on both sides under sterile conditions. The system was filled with nutrient medium (DMEM + 10% FCS + 1% P/S) and cultivated with 15mbar, 10s unidirectional flow. SCP1 cells were cultured at 37°C, 5% CO2 and 95% RH inside the different hydrogels. Hydrogels were loaded with cells into the bioreactor using a syringe system and were cultivated for at 7-28 days.

Results and Conclusion UV curable hydrogels appear to be easier and faster in handling, since crosslinking time point can be self-defined by UV light exposure, while Fibrin/Thrombin based hydrogels crosslink automatically when two components get in contact. UV exposure had no effect on cell viability. SCP1 cells revealed a rounded cell morphology compared to standard 2D cell culture in all tested hydrogels. UV curable hydrogels required longer hardening times (2-3 minutes) compared to fibrin hydrogels (few seconds). Fibrin hydrogels showed biodegradation after 12-14 days, while chemical modified polymers indicated no biodegradation after 28 days of culture.

This study summarizes advantages and disadvantages of several hydrogels tested for tissue engineering of bone tissue. Cultivation of MSCs over the time necessary for differentiation to bone will open new possibilities for 3D-analysis of bone physiology.

Stichwörter 3D Tissue Engineering, Hydrogel, Tissue Regeneration

Publication History

Article published online:
15 October 2020