The combination of tissue-engineered bone scaffolds with osteogenic induction molecules is an important strategy for critical-sized bone defects repair. We synthesized a novel thiolated chitosan/calcium carbonate composite microsphere (TCS-P24/CA) scaffold as a carrier for bone morphogenetic protein 2- (BMP2-) derived peptide P24 and evaluated the release kinetics of P24. The effect of TCS-P24/CA scaffolds on the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) was evaluated by scanning electron microscope (SEM), CCK-8, ALP assay, alizarin red staining, and PCR. A 5 mm diameter calvarial defect was created, then new bone formation was evaluated by Micro-CT and histological examination at 4 and 8 weeks after operation. We found the sequential release of P24 could last for 29 days. Meanwhile, BMSCs revealed spindle-shaped surface morphology, indicating the TCS-P24/CA scaffolds could support cell adhesion and mRNA levels for ALP, Runx2, and COL1a1 were significantly upregulated on TCS-10%P24/CA scaffold compared with other groups in vitro (). Similarly, the BMSCs exhibited a higher ALP activity as well as calcium deposition level on TCS-10%P24/CA scaffolds compared with other groups (). Analysis of in vivo bone formation showed that the TCS-10%P24/CA scaffold induced more bone formation than TCS-5%P24/CA, TCS/CA, and control groups. This study demonstrates that the novel TCS-P24/CA scaffolds might contribute to the delivery of BMP2-derived Peptide P24 and is considered to be a potential candidate for repairing bone defects.

中文翻译：

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硫代壳聚糖/碳酸钙复合微球支架顺序递送BMP2衍生肽P24进行骨再生

组织工程化骨支架与成骨诱导分子的结合是关键尺寸骨缺损修复的重要策略。我们合成了一种新型的硫醇化壳聚糖/碳酸钙复合微球（TCS-P24 / CA）支架，作为骨形态发生蛋白2-（BMP2-）衍生肽P24的载体，并评估了P24的释放动力学。通过扫描电子显微镜（SEM），CCK-8，ALP分析，茜素红染色和PCR评估了TCS-P24 / CA支架对骨髓间充质干细胞（BMSCs）增殖和分化的影响。产生5mm直径的颅骨缺损，然后在术后4周和8周通过Micro-CT和组织学检查评估新的骨形成。我们发现P24的顺序发布可能会持续29天。与此同时，）。同样，与其他组相比，BMSC在TCS-10％P24 / CA支架上表现出更高的ALP活性以及钙沉积水平（）。体内骨形成的分析表明，与TCS-5％P24 / CA，TCS / CA和对照组相比，TCS-10％P24 / CA支架诱导的骨形成更多。这项研究表明，新颖的TCS-P24 / CA支架可能有助于BMP2衍生肽P24的传递，并被认为是修复骨缺损的潜在候选者。