生物活性玻璃-二氧化锰复合支架的制备与表征

骨修复支架在植入缺损处后出现的炎症与氧化应激有关, 其中过氧化氢(H₂O₂)浓度过高是引起氧化应激的主要原因之一。二氧化锰(MnO₂)能够通过催化分解H₂O₂来消除植入物周围环境过量的H₂O₂, 同时催化H₂O₂分解产生的氧气(O₂)能够缓解骨缺损处因血供不足而导致的缺氧环境, 从而有利于骨组织再生与骨缺损修复。本研究采用简单的氧化还原法在3D打印制备的生物活性玻璃(BG)支架表面原位沉积MnO₂颗粒, 得到BG-MnO₂复合支架(BGM), 赋予BG支架清除H₂O₂的同时提供O₂的能力。研究结果表明, BGM支架表面沉积MnO₂含量随反应溶液中高锰酸钾浓度升高而增加, 其抗压强度随MnO₂含量增加而增强, 但这些支架的孔隙率和降解速度基本保持不变。更为重要的是, BGM支架能够在H₂O₂环境中持续催化分解H₂O₂产生O₂, 当不同Mn含量的BGM (BGM5和BMG9)支架在浓度为2 mmol/L的H₂O₂溶液中催化分解H₂O₂产生的O₂能使溶液中饱和氧浓度分别达到8.4和11 mg/L。细胞实验结果表明, BGM支架对骨髓间充质干细胞的增殖和碱性磷酸酶活性有一定促进作用。因此, BGM支架在骨组织修复领域具有较大的应用潜力。

Preparation and Characterization of Bioactive Glass-Manganese Dioxide Composite Scaffolds

Inflammation in bone defect after being implanted scaffold is related to oxidative stress, which is caused mainly by higher concentration of hydrogen peroxide (H₂O₂). Manganese dioxide (MnO₂) can catalyze H₂O₂ decomposition to decrease excessive H₂O₂ in the surrounding environment of scaffolds. Furthermore, the oxygen (O₂) generated by the decomposition of H₂O₂ can alleviate the hypoxia caused by insufficient blood supply in bone defects, which is conducive to bone tissue regeneration. Here, a simple redox method was proposed to deposit MnO₂ particles on the surface of 3D printed bioactive glass (BG) scaffolds for the preparation of BG-MnO₂ composite scaffolds (BGM), which endows BG-MnO₂ scaffolds with the ability of H₂O₂ scavenging and O₂ supplying simultaneously. The results showed that the MnO₂ content deposited on the surface of BGM scaffolds was increased with the increase of potassium permanganate concentration in the reaction solution, and the compressive strength of BGM scaffolds was increased with the increase of MnO₂ content. However, porosity and degradation rate of these scaffolds with or without MnO₂ remained the same. More importantly, BGM scaffolds can continuously catalyze the decomposition of H₂O₂ to produce O₂ in H₂O₂ environment. When BGM with different Mn content scaffolds (BMG5 and BGM9) catalyzed the decomposition of H₂O₂ to produce O₂ in 2 mmol/L H₂O₂ solution, the saturated oxygen concentration in the solution could reach 8.4 and 11 mg/L, respectively. In vitro cell experiments showed that BGM scaffolds could promote the proliferation and alkaline phosphatase activity of rabbit bone marrow mesenchymal stem cells. Hence, BGM scaffolds show great potential in bone regeneration.