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چکیده
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Various porous materials have been developed for bone repair and regeneration; however, their clinical application is often limited by rapid resorption, insufficient bioactivity, or inadequate mechanical requirements. This study introduces porous zirconolite (CaZrTi2O7) as a novel bioactive and osteoconductive bone substitute combining mechanical stability with controlled biodegradation. Porous zirconolite scaffolds were fabricated via solid-state reaction of zirconia, titania, and calcium carbonate, followed by sintering at 1200 °C. In vitro bioactivity was evaluated by immersion in simulated body fluid (SBF) for up to 28 days, with surface mineralization analyzed by XRD, FTIR, and SEM, and ion release quantified by ICP-AES. Biodegradation was assessed in citric acid-buffered solution through weight loss, porosity evolution, and compressive strength measurements. Biological responses were also examined using rat mesenchymal stem cells (MSCs) to evaluate proliferation, alkaline phosphatase (ALP) activity, and osteogenic protein expression. Results demonstrated progressive formation of a carbonate-substituted apatite layer after 21 days in SBF, accompanied by controlled release of Ca2+ (≤12.8 ppm), Zr4+ (≤6.4 ppm), and Ti4+ (≤3.2 ppm) without significant pH variation. Biodegradation tests revealed gradual weight loss (∼0.6 %), increased porosity (48 %–52 %), and moderate reduction in compressive strength (32 MPa–26 MPa) over 28 days. MSC assays showed enhanced proliferation, elevated ALP activity, and significant upregulation of osteogenic markers at both mRNA and protein levels. Collectively, these findings demonstrate that zirconolite scaffolds possess adequate mechanical properties, bioactivity, structural integrity, and osteoconductivity, emphasizing their potential as synthetic bone graft materials.
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