Design and evaluation of sodium alginate/polyvinyl alcohol blend hydrogel for 3D bioprinting cartilage scaffold: molecular dynamics simulation and experimental method

To determine the optimum composition of AS/PVA for bioprinting cartilage scaffold, a molecular simulation combining experimental method was employed to investigate the microstructure, physicochemical properties and printability of AS/PVA blending hydrogels at different compositions. The compatibility analysis results show that SA and PVA have a good compatibility, they are miscible at any compositions. Mechanical properties analysis indicates that the tensile strength of 8SA/2PVA is the best, and compared with 8SA/2PVA, 7SA/3PVA possesses a better toughness and similar tensile strength. Moreover, FFV value and pore size decrease with the increase of PVA content, indicating the incorporation of PVA makes the system denser and pore size smaller, and the hydrogel of 8SA/2PVA possesses the optimal pore structure for the proliferation of chondrocytes. The main reason behind the conclusions obtained above is attributed to the strong hydrogen bond and intermolecular interaction between SA and PVA molecular chains. Finally, the results of printability indicates that, due to the fluidity of PVA, the forming quality becomes worse with the increase of PVA content, and when the PVA content in hydrogel precursors is within 30 wt.%, the forming quality is relatively good. Comprehensive considering the results above, the blend hydrogel of 8SA/2PVA was selected out and considered to be the most suitable for 3D printing cartilage scaffolds.