Development of Bioactive 3D Printed MC/Al/Gel/HA Scaffolds with Enhanced Printability, Flexibility and Mechanical Strength

Achieving high shape fidelity is critical for the fabrication of functional 3D printed bone scaffolds. This study aimed to develop a printable and bioactive hydrogel scaffold suitable for bone tissue engineering by incorporating methylcellulose (MC) and hydroxyapatite (HA) into an alginate/gelatin (AlGel) hydrogel ink. The rheological studies are carried out for these hydrogels. Following this, degradation studies, morphological analysis are conducted for the 3D printed scaffolds. Mechanical properties, wettability, and bioactivity are analyzed following with cell culture and biomineralization studies. Rheological studies also demonstrated that enhanced printability is related to the higher viscosity of the hydrogels after MC incorporation. Notably, printability increased from 0.59 to 0.96 by the addition of 3 wt/v% MC. MC also highly improved the ductility of the scaffolds. HA enhanced both the bioactivity and mechanical strength. The compressive strength and % strain of the AlGelMC3HA1 scaffolds are 0.78 MPa and 100%, respectively. All samples degraded within 9 days. All samples has relatively high % viability of MC3T3 pre-osteoblast cells on day 3 which indicated cytocompatibility of the scaffolds. The calcium deposition is confirmed via Alizarin Red S staining for all study groups on day 14. Overall, the scaffolds show high potential for bone tissue engineering applications.