Enhancing bone tissue engineering with calcium and strontium nanoparticles immobilized on HKUST-1

Abstract

Recent advances in osteoimmunology have led the focus on the immunomodulatory design of metal–organic framework (MOF)-based porous materials for encouraging bone repair by influencing the immune microenvironment using implanting biomaterials. Despite the growing interest in porous materials, few research studies have been done on how extracellular Sr2+ and Ca2+ loaded in MOFs leads the organism toward optimal osteogenesis. In this study, in vitro evaluations showed that both Sr2+ and Ca2+ nanoparticles have a dual effect, stimulating matrix secretion by osteoblasts while suppressing matrix resorption by osteoclasts. Sr2+ significantly increased RUNX2 transcriptional activity and phosphorylation in gene expression evaluation. On day seven, hBMSC cells on HKUST-1@CaNPs/SrNPs showed a significant increase in collagen gene expression compared to HKUST-1@CaNPs/SrNPs@PEG, indicating a high level of proliferation and differentiation. At the same time, the HKUST-1@SrNPs hBMSC cells expressed the RUNX2 gene at a much higher level than the other groups. ALP activity was measured on days 7 and 14 of culture to see how it compares to more extended incubation periods. As the culture time for HKUST-1@SrNPs and HKUST-1@CaNPs/SrNPs was extended from 7 to 14 days, the ALP activity was shown to rise. Findings indicated that HKUST-1@CaNPs/SrNPs improved hBMSC osteogenic differentiation potential. In conclusion, HKUST-1@CaNPs/SrNPs could show promising results for bone tissue engineering.

Keywords

• HKUST-1
• Calcium
• Strontium
• Bone tissue engineering
• RUNX2 gene expression
• Metal-organic framework