Coelho Soraia Alexandra Ramos, Almeida Jose Carlos, Unalan Irem, Detsch Rainer, Miranda Salvado Isabel Margarida, Boccaccini Aldo R, Fernandes Maria Helena Vaz
Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials (CICECO/UA), University of Aveiro, 3810-193 Aveiro, Portugal.
Institute of Biomaterials, Department of Materials Science and Engineering, Friedrich-Alexander-University of Erlangen-Nuremberg, Cauerstraße 6, 91058 Erlangen, Germany.
ACS Biomater Sci Eng. 2021 Feb 8;7(2):491-506. doi: 10.1021/acsbiomaterials.0c01546. Epub 2021 Jan 26.
Poly(dimethylsiloxane) (PDMS)-SiO-CaO-based hybrid materials prepared by sol-gel have proved to be very promising materials for tissue engineering applications and drug-delivery systems. These hybrids are biocompatible and present osteogenic and bioactive properties supporting osteoblast attachment and bone growth. The incorporation of therapeutic elements in these materials, such as boron (B) and calcium (Ca), was considered in this study as an approach to develop biomaterials capable of stimulating bone regeneration. The main purpose of this work was thus to produce, by sol-gel, bioactive and biocompatible hybrid materials of the PDMS-SiO-BO-CaO system, capable of a controlled Ca and B release. Different compositions with different boron amounts were prepared using the same precursors resulting in different monolithic materials, with distinct structures and microstructures. Structural features were assessed by Fourier transform infrared (FT-IR) spectrometry and solid-state nuclear magnetic resonance (NMR) techniques, which confirmed the presence of hybrid bonds (Si-O-Si) between organic (PDMS) and inorganic phase (tetraethyl orthosilicate (TEOS)), as well as borosiloxane bonds (B-O-Si). From the B NMR results, it was found that Ca changes the boron coordination, from trigonal (BO) to tetrahedral (BO). Scanning electron microscopy (SEM) micrographs and N isotherms showed that the incorporation of boron modifies the material's microstructure by increasing the macroporosity and decreasing the specific surface area (SSA). In vitro tests in simulated body fluid (SBF) showed the precipitation of a calcium phosphate layer on the material surface and the controlled release of therapeutic ions. The cytocompatibility of the prepared hybrids was studied with bone marrow stromal cells (ST-2 cell line) by analyzing the cell viability and cell density. The results demonstrated that increasing the dilution rate of extraction medium from the hybrids leads to improved cell behavior. The relationship between the in vitro response and the structural and microstructural features of the materials was explored. It was shown that the release of calcium and boron ions, determined by the hybrid structure was crucial for the observed cells behavior. Although not completely understood, the encouraging results obtained constitute an incentive for further studies on this topic.
通过溶胶 - 凝胶法制备的聚二甲基硅氧烷（PDMS）-SiO-CaO基杂化材料已被证明是用于组织工程应用和药物递送系统的非常有前途的材料。这些杂化物具有生物相容性，并具有支持成骨细胞附着和骨生长的成骨和生物活性特性。本研究考虑在这些材料中掺入治疗元素，如硼（B）和钙（Ca），作为开发能够刺激骨再生的生物材料的一种方法。因此，这项工作的主要目的是通过溶胶 - 凝胶法制备PDMS-SiO-BO-CaO系统的生物活性和生物相容性杂化材料，使其能够控制钙和硼的释放。使用相同的前驱体制备了具有不同硼含量的不同组成，从而得到具有不同结构和微观结构的不同整体材料。通过傅里叶变换红外（FT-IR）光谱和固态核磁共振（NMR）技术评估结构特征，证实了有机相（PDMS）和无机相（正硅酸四乙酯（TEOS））之间存在杂化键（Si-O-Si）以及硼硅氧烷键（B-O-Si）。从硼核磁共振结果发现，钙改变了硼的配位，从三角（BO）变为四面体（BO）。扫描电子显微镜（SEM）显微照片和N等温线表明，硼的掺入通过增加大孔率和降低比表面积（SSA）来改变材料的微观结构。在模拟体液（SBF）中的体外测试表明材料表面有磷酸钙层沉淀以及治疗离子的控制释放。通过分析细胞活力和细胞密度，研究了制备的杂化物与骨髓基质细胞（ST-2细胞系）的细胞相容性。结果表明，提高杂化物提取介质的稀释率会改善细胞行为。探索了体外反应与材料结构和微观结构特征之间的关系。结果表明，由杂化结构决定的钙和硼离子的释放对于观察到的细胞行为至关重要。尽管尚未完全理解，但所获得的令人鼓舞的结果为进一步研究该主题提供了动力。
