Biomaterials and Tissue Engineering Laboratory, School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India.
J Mater Chem B. 2021 Sep 14;9(34):6856-6869. doi: 10.1039/d1tb00255d. Epub 2021 Aug 16.
Biomimetic delivery of osteoinductive growth factors via an osteoconductive matrix is an interesting approach for stimulating bone regeneration. In this context, the bone extracellular matrix (ECM) has been explored as an optimal delivery system, since it releases growth factors in a spatiotemporal manner from the matrix. However, a bone ECM hydrogel alone is weak, unstable, and prone to microbial contamination and also has been reported to have significantly reduced bone morphogenic protein-2 (BMP-2) post decellularization. In the present work, a microsphere embedded osteoinductive decellularized bone ECM/oleoyl chitosan based hydrogel construct (BOC) was developed as a matrix allowing dual delivery of an anti-resorptive drug (alendronate, ALN, via the microspheres) and BMP-2 (via the hydrogel) for a focal tibial defect in a rabbit model. The synthesized gelatin microspheres (GMs) were spherical in shape with diameter ∼32 μm as assessed by SEM analysis. The BOC construct showed sustained release of ALN and BMP-2 under the studied conditions. Interestingly, amniotic membrane-derived stem cells (HAMSCs) cultivated on the hydrogel construct demonstrated excellent biocompatibility, cell viability, and active proliferation potential. Additionally, cell differentiation on the constructs showed an elevated expression of osteogenic genes in an RT-PCR study along with enhanced mineralized matrix deposition as demonstrated by alkaline phosphatase (ALP) assay and alizarin red assay. The hydrogel construct was witnessed to have improved neo-vascularization potential in a chick chorioalantoic membrane (CAM) assay. Also, histological and computed tomographic findings evidenced enhanced bone regeneration in the group treated with the BOC/ALN/BMP hydrogel construct in a rabbit tibial defect model. To conclude, the developed multifunctional hydrogel construct acts as an osteoinductive and osteoconductive platform facilitating controlled delivery of ALN and BMP-2, essential for stimulating bone tissue regeneration.
仿生递送具有成骨活性的生长因子通过一种骨传导性基质是一种刺激骨再生的有趣方法。在这种情况下，骨细胞外基质 (ECM) 已被探索作为一种最佳的递送系统，因为它可以从基质中以时空方式释放生长因子。然而，单独的骨 ECM 水凝胶本身很脆弱、不稳定，容易受到微生物污染，并且据报道，脱细胞化后骨形态发生蛋白-2 (BMP-2) 的含量显著降低。在本工作中，开发了一种微球嵌入的具有成骨活性的脱细胞骨 ECM/油酰壳聚糖基水凝胶构建体 (BOC)，作为一种基质，允许通过微球双重递抗吸收药物 (阿仑膦酸钠，ALN) 和 BMP-2 (通过水凝胶) 用于兔模型中的局灶性胫骨缺损。通过 SEM 分析评估，合成的明胶微球 (GMs) 呈球形，直径约为 32 μm。BOC 构建体在研究条件下显示出 ALN 和 BMP-2 的持续释放。有趣的是，在水凝胶构建体上培养的羊膜来源的干细胞 (HAMSCs) 表现出优异的生物相容性、细胞活力和活跃的增殖潜力。此外，在 RT-PCR 研究中，细胞在构建体上的分化显示出成骨基因的表达升高，碱性磷酸酶 (ALP) 测定和茜素红测定显示增强的矿化基质沉积。水凝胶构建体在鸡胚绒毛尿囊膜 (CAM) 试验中被证明具有改善的新血管生成潜力。此外，组织学和计算机断层扫描结果表明，在兔胫骨缺损模型中，用 BOC/ALN/BMP 水凝胶构建体治疗的组中增强了骨再生。总之，所开发的多功能水凝胶构建体作为一种具有成骨活性和骨传导性的平台，促进 ALN 和 BMP-2 的控制释放，这对于刺激骨组织再生至关重要。
