Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, PR China; National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510006, PR China.
Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, PR China.
Carbohydr Polym. 2018 Sep 1;195:225-234. doi: 10.1016/j.carbpol.2018.04.090. Epub 2018 Apr 24.
Inspired by the natural extracellular matrix, the organic-inorganic composite nanofibers are promising scaffolds for bone tissue engineering. Chitosan-based nanofibers are widely used as bone tissue engineering scaffolds with good biocompatibility but pungent solvents are frequently used for its processing. Carboxymethyl chitosan (CMCS), a water-soluble derivative of chitosan, has better biodegradability and bioactivity which allows CMCS to chelate Ca and induce the deposition of apatite. Moreover, with water as solvent, CMCS nanofibers avoid the acidic salt removal comparing to electrospun-chitosan. In this study, we successfully prepared uniform CMCS nanofibers with the aid of polyethylene oxide (PEO) and obtained the optimized conditions with a voltage of 25 kV and PEO of molecular weight 1000 kDa. We further prepared hydroxyapatite (HA) coated electrospun CMCS nanofibers by biomimetic mineralization using 5 times simulated body fluid. The promotion of osteogenic differentiation of mouse bone marrow stromal cells (mBMSCs) in vitro was evaluated on the nanofibers scaffolds. Cell experiments revealed that CMCS-HA composite nanofibers increased the ALP activity. The gene expression level of Runx2 and ALP were about 1.6 and 4.3 folds at the 7 days, and 5.1 and 10 folds at the 14 days on CMCS-HA nanofibrous membranes than that on CMCS alone samples. The level of OCN increased by 24 and 1.5 times on the CMCS-HA scaffolds than CMCS scaffolds at the 14 and 21 days. In vivo new bone formation by nanofiber scaffolds was investigated in a critical-size rat calvarial bone defect model. Micro-CT results showed that the whole defect was covered by new bone after CMCS-HA filling the defect for 12 weeks. The results of H&E staining and Masson's trichrome staining on histological sections further confirmed that composite nanofibers promoted new bone formation and maturation.
受天然细胞外基质的启发，有机-无机复合纳米纤维是骨组织工程有前途的支架。壳聚糖基纳米纤维由于具有良好的生物相容性而被广泛用作骨组织工程支架，但通常需要使用刺激性溶剂进行加工。羧甲基壳聚糖（CMCS）是壳聚糖的水溶性衍生物，具有更好的生物降解性和生物活性，可使 CMCS 螯合 Ca 并诱导磷灰石的沉积。此外，由于使用水作为溶剂，与静电纺丝壳聚糖相比，CMCS 纳米纤维避免了去除酸性盐。在这项研究中，我们在聚氧化乙烯（PEO）的辅助下成功制备了均匀的 CMCS 纳米纤维，并获得了优化条件，即电压为 25 kV 和分子量为 1000 kDa 的 PEO。我们进一步通过使用 5 倍的模拟体液进行仿生矿化，制备了羟基磷灰石（HA）涂覆的静电纺丝 CMCS 纳米纤维。在纳米纤维支架上评估了体外对小鼠骨髓基质细胞（mBMSCs）成骨分化的促进作用。细胞实验表明，CMCS-HA 复合纳米纤维增加了碱性磷酸酶（ALP）的活性。在第 7 天，Runx2 和 ALP 的基因表达水平分别约为 CMCS 纳米纤维膜上的 1.6 倍和 4.3 倍，在第 14 天，Runx2 和 ALP 的基因表达水平分别约为 CMCS 纳米纤维膜上的 5.1 倍和 10 倍。在第 14 和 21 天，OCN 的水平在 CMCS-HA 支架上分别比 CMCS 支架增加了 24 倍和 1.5 倍。在大鼠颅骨临界尺寸骨缺损模型中研究了纳米纤维支架的体内新骨形成。微 CT 结果表明，在 CMCS-HA 填充缺陷 12 周后，整个缺陷被新骨覆盖。组织学切片的 H&E 染色和 Masson 三色染色的结果进一步证实了复合纳米纤维促进了新骨的形成和成熟。
