Physical barrier membranes have been used to release active substances to treat critical bone defects; however, hydrophilic membranes do not present a prolonged release capacity. In this sense, hydrophobic membranes have been tested. Thus, this study aimed to develop hydrophobic membranes based on mixtures of ureasil–polyether-type materials containing incorporated dexamethasone (DMA) for the application in guided bone regeneration. The physicochemical characterization and biological assays were carried out using small-angle X-ray scattering (SAXS), an in vitro DMA release study, atomic force microscopy (AFM), a hemolysis test, and in vivo bone formation. The swelling degree, SAXS, and release results revealed that the u-PPO400/2000 membrane in the proportion of 70:30 showed swelling (4.69% ± 0.22) similar to the proportions 90:10 and 80:20, and lower than the proportion 60:40 (6.38% ± 0.49); however, an equal release percentage after 134 h was observed between the proportions 70:30 and 60:40. All u-PPO materials presented hemocompatibility (hemolysis ≤2.8%). AFM results showed that the treatments with or without DMA did not present significant differences, revealing a flat/smooth surface, with no pores and/or crystalline precipitates. Finally, in vivo results revealed that for both the commercial hydrophilic membrane and u-PPO400/2000 (70:30) after 60 days, the bone formation volume was 21%. In conclusion, hybrid membranes present unique characteristics for treating critical bone defects, considering the delayed and prolonged release results associated with the physical barrier capacity.

中文翻译：

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用于骨引导再生的地塞米松负载脲醛疏水膜

物理屏障膜已被用来释放活性物质来治疗严重的骨缺损；然而，亲水膜不具有长期释放能力。从这个意义上说，疏水膜已经过测试。因此，本研究旨在开发基于含有地塞米松（DMA）的脲硅聚醚型材料混合物的疏水膜，用于引导骨再生。使用小角 X 射线散射 (SAXS)、体外 DMA 释放研究、原子力显微镜 (AFM)、溶血测试和体内骨形成进行理化表征和生物测定。溶胀度、SAXS和释放结果显示，70:30比例的u-PPO400/2000膜的溶胀率（4.69%±0.22）与90:10和80:20比例相似，并且低于比例60:40（6.38%±0.49）；然而，134 小时后，在 70:30 和 60:40 的比例之间观察到相同的释放百分比。所有u-PPO材料均表现出血液相容性（溶血≤2.8%）。AFM 结果表明，使用或不使用 DMA 的处理没有表现出显着差异，显示出平坦/光滑的表面，没有孔隙和/或结晶沉淀物。最后，体内结果显示，商业亲水膜和u-PPO400/2000（70:30）在60天后，骨形成量均为21%。总之，考虑到与物理屏障能力相关的延迟和延长释放结果，混合膜呈现出治疗严重骨缺损的独特特性。