Development of montmorillonite-based 3D bio-printable bioink for bone tissue engineering

The development of bioinks with optimal printability, mechanical stability, and biocompatibility is critical for advancing bone tissue engineering. In this study, we present a Montmorillonite-based 3D bio-printable bioink formulated using gelatin, low-methoxy pectin, and Montmorillonite K10 (MMT). The bioink was systematically optimized for its rheological properties, printability, and cross‑linking efficiency using calcium chloride and glutaraldehyde. Rheological assessments confirmed a shear-thinning behavior, facilitating smooth extrusion during bioprinting, while the viscoelastic analyses indicated a formulation-dependent balance between structural integrity and flexibility. Mechanical testing revealed that incorporation of MMT significantly enhanced the tensile strength and compressibility, essential for maintaining scaffold stability post-printing. Degradation studies further demonstrated the integrity of scaffolds over 28 days, with a controlled degradation profile, suitable for tissue integration. Biocompatibility was evaluated using Alamar Blue cytotoxicity assay and confocal imaging of hFOB 1.19 osteoblasts, which confirmed a high cell viability and progressive proliferation over seven days. SEM analysis highlighted a porous microarchitecture conducive to cell attachment and nutrient diffusion. The swelling behavior of the scaffolds indicated sufficient fluid retention to support long-term cell culture. Overall, the formulated bioink exhibited excellent printability, mechanical robustness, and cytocompatibility, making it a promising candidate for 3D bioprinted bone scaffolds. These findings provide a foundation for further investigations about in vivo performance, paving the way for its potential application in regenerative medicine.