Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt.
Microbiology Department, Medical Research Institute, Alexandria University, Alexandria, 21561, Egypt.
Int J Nanomedicine. 2021 Feb 12;16:1103-1126. doi: 10.2147/IJN.S298297. eCollection 2021.
Besides its antimicrobial action, doxycycline (DX) has lately been repurposed as a small-molecule drug for osteogenic purposes. However, osteogenic DX application is impeded by its dose-dependent cytotoxicity. Further, high-dose DX impairs cell differentiation and mineralization.
Integrating DX into a biomaterial-based delivery system that can control its release would not only ameliorate its cytotoxic actions but also augment its osteogenic activity. In this work, we managed to engineer novel composite DX-hydroxyapatite-polycaprolactone nanoparticles (DX/HAp/PCL) to modify DX osteogenic potential.
Employing a 2-factorial design, we first optimized HApN for surface-area attributes to maximize DX loading. Composite DX/HAp/PCL were then realized using a simple emulsification technique, characterized using various in vitro methods, and evaluated for in vitro osteogenesis.
The developed HApN exhibited a favorable crystalline structure, Ca:P elemental ratio (1.67), mesoporous nature, and large surface area. DX/HAp/PCL achieved the highest reported entrapment efficiency (94.77%±1.23%) of DX in PCL-based particles. The developed composite system achieved controlled release of the water-soluble DX over 24 days. Moreover, the novel composite nanosystem managed to significantly ameliorate DX cytotoxicity on bone-marrow stem cells, as well as enhance its overall proliferation potential. Alkaline phosphatase and mineralization assays revealed superior osteodifferentiation potential of the composite system. Quantification of gene expression demonstrated that while DX solution was able to drive bone-marrow stem cells down the osteogenic lineage into immature osteoblasts after 10-day culture, the innovative composite system allowed maturation of osteodifferentiated cells. To the best of our knowledge, this is the first work to elaborate the impact of DX on the expression of osteogenic genes: , OSP, and BSP. Further, the osteogenicity of a DX-loaded particulate-delivery system has not been previously investigated.
Our findings indicate that repurposing low-dose DX in complementary biomaterial-based nanosystems can offer a prominent osteogenic candidate for bone-regeneration purposes.
除了其抗菌作用外，多西环素（DX）最近也被重新用作具有成骨作用的小分子药物。然而，成骨 DX 的应用受到其剂量依赖性细胞毒性的阻碍。此外，高剂量的 DX 会损害细胞分化和矿化。
将 DX 整合到基于生物材料的递药系统中，可以控制其释放，不仅可以改善其细胞毒性作用，还可以增强其成骨活性。在这项工作中，我们成功地设计了新型复合 DX-羟基磷灰石-聚己内酯纳米粒子（DX/HAp/PCL）来修饰 DX 的成骨潜力。
采用 2 因素设计，我们首先优化了 HApN 的表面积属性，以最大限度地提高 DX 的负载量。然后使用简单的乳化技术制备复合 DX/HAp/PCL，用各种体外方法进行表征，并评价其体外成骨作用。
所开发的 HApN 表现出有利的结晶结构、Ca:P 元素比（1.67）、介孔性质和大的表面积。DX/HAp/PCL 实现了 PCL 基粒子中最高报道的 DX 包封效率（94.77%±1.23%）。开发的复合系统能够在 24 天内控制水溶性 DX 的释放。此外，新型复合纳米系统成功地显著改善了 DX 对骨髓基质细胞的细胞毒性，并增强了其整体增殖潜力。碱性磷酸酶和矿化试验显示出该复合系统具有优越的成骨分化潜力。基因表达的定量分析表明，虽然 DX 溶液在 10 天培养后能够将骨髓基质细胞沿成骨谱系诱导为未成熟成骨细胞，但创新的复合系统允许成骨分化细胞成熟。据我们所知，这是第一项阐述 DX 对成骨基因表达的影响的工作： 、OSP 和 BSP。此外，以前没有研究过负载 DX 的颗粒递送系统的成骨作用。
我们的研究结果表明，将低剂量的 DX 重新用于互补的基于生物材料的纳米系统中，可以为骨再生目的提供一种有前途的成骨候选物。
