School of Materials Science and Engineering, Tongji University, Shanghai 201804, China.
Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.
Mater Sci Eng C Mater Biol Appl. 2019 Dec;105:110076. doi: 10.1016/j.msec.2019.110076. Epub 2019 Aug 12.
The composite scaffolds of bioactive glasses and polymers are often used in bone regeneration which could improve the stiffness, compressive strength and bioactivity of polymers while maintaining the osteoconductivity and osteoinductivity of bioactive glasses. But due to complicated situations and limitations of compositing process, the prepared composite materials have low uniformity and obvious phase separation, leading to problems such as poor mechanical properties and inferior new bone formation capacity. In this paper, a modified sol-gel processing technique was used to realize the homogeneous inorganic-organic composites. After hydrolysis of the metal alkoxide, the sol was mixed with the aqueous solution of polyvinyl alcohol (PVA), and through gelation and chemical reaction, the mixture was solidified into the inorganic-organic composite hydrogel. The composites showed as a uniform single phase with interpenetrating networks of PVA gel and borosilicate gel (BG) that chemically and physically interacted at the scale of molecular or nanometer, therefore PVA-BG hybrids were obtained. When immersed in phosphate-buffered saline, the PVA-BG hybrid-derived scaffolds released beneficial ions into the medium and converted to hydroxyapatite. The scaffolds were not toxic to the rat bone marrow-derived mesenchymal stem cells (rBMSCs), and supported rBMSCs proliferation. Furthermore, the alkaline phosphatase activity of the rBMSCs and the expression levels of osteogenic-related genes (alkaline phosphatase, osteocalcin and runt-related transcription factor 2) increased significantly with increasing amount of BG in the hybrid scaffolds. Finally, the bone defect repair results of critical-sized femoral condyle defect rat model demonstrated that PVA-BG hybrid scaffolds could enhance bone regeneration compared with PVA scaffolds. The results suggested that PVA-BG hybrid scaffolds may be a promising biomaterial for bone regeneration.
生物活性玻璃和聚合物的复合支架常用于骨再生，可提高聚合物的刚度、抗压强度和生物活性，同时保持生物活性玻璃的骨传导性和骨诱导性。但由于复合过程的复杂情况和限制，所制备的复合材料均匀性低，相分离明显，导致力学性能差、新骨形成能力差等问题。本文采用改进的溶胶-凝胶工艺实现了均匀的无机-有机复合材料。金属醇盐水解后，溶胶与聚乙烯醇（PVA）的水溶液混合，通过凝胶化和化学反应，混合物固化成无机-有机复合水凝胶。复合材料表现出均匀的单相，具有 PVA 凝胶和硼硅酸盐凝胶（BG）的互穿网络，它们在分子或纳米尺度上发生化学和物理相互作用，从而得到 PVA-BG 杂化材料。当浸入磷酸盐缓冲盐溶液中时，PVA-BG 杂化衍生的支架将有益离子释放到介质中，并转化为羟基磷灰石。支架对大鼠骨髓间充质干细胞（rBMSCs）没有毒性，并支持 rBMSCs 的增殖。此外，rBMSCs 的碱性磷酸酶活性和骨形成相关基因（碱性磷酸酶、骨钙素和 runt 相关转录因子 2）的表达水平随着杂化支架中 BG 含量的增加而显著增加。最后，对临界尺寸股骨髁缺损大鼠模型的骨缺损修复结果表明，与 PVA 支架相比，PVA-BG 杂化支架可增强骨再生。结果表明，PVA-BG 杂化支架可能是一种有前途的骨再生生物材料。
