Fabrication of a calcium cement-incorporated composite hydrogel scaffold via extrusion-based 3D bioprinting for bone tissue engineering.

A composite hydrogel bio-ink designated CuraGel was developed for extrusion-based 3D bioprinting of bone tissue engineering scaffolds. The formulation comprised gelatin (3% w/v), guar gum (1% w/v), sodium alginate (4% w/v), and β-tricalcium phosphate (β-TCP; 1% w/v) in 10 mL distilled water. Guar gum was incorporated as a rheological modifier to enhance viscosity, shape fidelity, and water retention during the printing process. Post-printing ionic crosslinking in 2% calcium chloride (CaCl2) for 3 min yielded structurally stable scaffolds with well-defined porous architectures. Swelling kinetics studies demonstrated a swelling ratio of approximately 840% at equilibrium, reached at approximately 300 min, indicating high water retention capacity suitable for nutrient diffusion in bone tissue applications. Hemocompatibility assessment through visual RBC lysis evaluation, clotting time observation across a 90-min period, and brightfield RBC morphology analysis collectively demonstrated that CuraGel does not induce erythrocyte lysis, disrupt normal coagulation, or alter red blood cell morphology. These findings indicate that CuraGel possesses the rheological, structural, and hemocompatible properties required for scaffold-based bone tissue engineering applications.