Zr-based metal-organic framework nanocrystals improve the osteoinductivity and osteogenicity of alginate/methyl cellulose bioink

Addressing critical-sized bone defects poses significant challenges due to the limitations of natural bone regeneration and conventional treatments like tissue transplantation. Bone tissue engineering and 3D bioprinting offer promising solutions by creating customized, biomimetic scaffolds. This study explores the innovative use of UiO-66 metal-organic framework (MOF) nanocrystals to enhance the osteoinductive and osteogenic properties of 3D bioprinted scaffolds. UiO-66 nanocrystals were synthesized and characterized, demonstrating uniform morphology and highly crystalline structure. These nanocrystals were then incorporated into alginate/methyl cellulose (AL/MC) hydrogel at various concentrations and print parameters were optimized based on physicochemical properties. AL/MC/UiO-66 optimized under specific conditions was then used as a bioink to 3D bioprint scaffolds including MC3T3-E1 preosteoblasts. Cell viability and osteogenic differentiation characteristics were assessed. The results demonstrated that AL/MC scaffolds with 2 % (w/v) UiO-66 nanocrystals significantly promoted osteogenic differentiation, as indicated by increased alkaline phosphatase (ALP) activity and upregulated expression of osteogenic markers (Runx-2, COLI, OCN). This study highlights the novel application of UiO-66 nanocrystals in 3D bioprinted scaffolds, presenting a promising strategy for enhancing bone regeneration.