A variety of controlled release carriers for bone morphogenetic protein 2 (BMP‐2) delivery have been developed and tested in animal models. An alginate‐based polyelectrolyte complex (PEC) for controlled release of low‐dose BMP‐2 has shown promising results in preclinical research. However, the poor handling properties and long‐term stability of PEC need to be improved for translational applications. This study aimed to address these limitations of alginate‐based PEC by employing a freeze‐drying technique. The size and structure of freeze‐dried PEC (FD‐PEC) were maintained with the addition of a cryoprotectant, trehalose. The release profile of BMP‐2 from FD‐PEC was similar to that of freshly prepared PEC. In vitro bioactivity analysis of the released BMP‐2 showed that the carrier performance of PEC was not compromised by freeze‐drying up to three‐month storage at room temperature. BMP‐2‐bound FD‐PEC induced comparable bone formation to that using freshly prepared regular PEC in a rat posterolateral spinal fusion model. These results suggest that FD‐PEC is capable of delivering low‐dose BMP‐2 and could be developed as an off‐the‐shelf product for translational applications. The simplicity of this preservation method provides promise for the translational application of PEC.

中文翻译：

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通过冷冻干燥技术改善聚电解质复合物的处理性能和长期稳定性，用于低剂量骨形态发生蛋白 2 递送。

已经开发了多种用于骨形态发生蛋白 2 (BMP-2) 递送的控释载体，并在动物模型中进行了测试。一种用于控制释放低剂量 BMP-2 的藻酸盐基聚电解质复合物 (PEC) 在临床前研究中显示出有希望的结果。然而，PEC 较差的处理性能和长期稳定性需要改进以用于转化应用。本研究旨在通过采用冷冻干燥技术来解决基于藻酸盐的 PEC 的这些局限性。添加冷冻保护剂海藻糖后，冷冻干燥的 PEC (FD-PEC) 的大小和结构得以保持。FD-PEC 中 BMP-2 的释放曲线与新鲜制备的 PEC 相似。释放的 BMP-2 的体外生物活性分析表明，PEC 的载体性能不会因在室温下冷冻干燥长达三个月而受到影响。在大鼠后外侧脊柱融合模型中，结合 BMP-2 的 FD-PEC 诱导的骨形成与使用新鲜制备的常规 PEC 相似。这些结果表明 FD-PEC 能够提供低剂量的 BMP-2，并且可以开发为用于转化应用的现成产品。这种保存方法的简单性为 PEC 的翻译应用提供了希望。这些结果表明 FD-PEC 能够提供低剂量的 BMP-2，并且可以开发为用于转化应用的现成产品。这种保存方法的简单性为 PEC 的翻译应用提供了希望。这些结果表明 FD-PEC 能够提供低剂量的 BMP-2，并且可以开发为用于转化应用的现成产品。这种保存方法的简单性为 PEC 的翻译应用提供了希望。