Guo Ya-Ping, Guan Jun-Jie, Yang Jun, Wang Yang, Zhang Chang-Qing, Ke Qin-Fei
The Education Ministry Key Lab of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234, P. R. China.
J Mater Chem B. 2015 Jun 21;3(23):4679-4689. doi: 10.1039/c5tb00175g. Epub 2015 May 20.
The fabrication of bone scaffolds with interconnected porous structure, adequate mechanical properties, excellent biocompatibility and osteoinductivity presents a great challenge. Herein, a hybrid nanostructured hydroxyapatite-chitosan (HA-CS) composite scaffold has been fabricated according to the following steps: (i) the deposition of brushite-CS on a CS fibre porous scaffold by a dip-coating method; and (ii) the formation of a hybrid nanostructured HA-CS composite scaffold by the in situ conversion of brushite to HA using a bioinspired mineralization process. The hybrid HA-CS composite scaffold possesses three-dimensional (3D) interconnected pores with pore sizes of 30-80 μm. The HA rods with a length of ∼200 nm and width of ∼50 nm are perpendicularly oriented to the CS fibres. Interestingly, the abovementioned HA rods are composed of many smaller nanorods with a length of ∼40 nm and width of ∼10 nm oriented along the c-axis. The hybrid nanostructured HA-CS composite scaffold exhibits good mechanical properties with a compression strength of 9.41 ± 1.63 MPa and an elastic modulus of 0.17 ± 0.02 GPa, which are well-matched to those of trabecular bone. The influences of the hybrid HA-CS composite scaffold on cells have been investigated using human bone marrow stem cells (hBMSCs) as cell model and the CS fibre porous scaffold as the control sample. The hybrid HA-CS composite scaffold not only supports the adhesion and proliferation of hBMSCs, but also improves the osteoinductivity. The alkaline phosphatase activity and mineralization deposition on the hybrid HA-CS composite scaffold are higher than those on the CS fibre porous scaffold. Moreover, the hybrid HA-CS composite scaffold can promote the formation of new bone in rat calvarial defects as compared with the CS fibre porous scaffold. The excellent biocompatibility, osteoinductivity and mechanical properties suggest that the hybrid nanostructured HA-CS composite scaffold has great potential for bone tissue engineering.
制备具有相互连通的多孔结构、足够的力学性能、优异的生物相容性和骨诱导性的骨支架是一项巨大的挑战。在此，一种混合纳米结构的羟基磷灰石-壳聚糖（HA-CS）复合支架已按以下步骤制备：（i）通过浸涂法在CS纤维多孔支架上沉积透钙磷石-CS；（ii）利用仿生矿化过程将透钙磷石原位转化为HA，形成混合纳米结构的HA-CS复合支架。该混合HA-CS复合支架具有三维（3D）相互连通的孔隙，孔径为30-80μm。长度约为200nm、宽度约为50nm的HA棒垂直于CS纤维排列。有趣的是，上述HA棒由许多沿c轴排列的长度约为40nm、宽度约为10nm的较小纳米棒组成。该混合纳米结构的HA-CS复合支架表现出良好的力学性能，抗压强度为9.41±1.63MPa，弹性模量为0.17±0.02GPa，与松质骨的力学性能非常匹配。以人骨髓干细胞（hBMSCs）为细胞模型，以CS纤维多孔支架为对照样品，研究了混合HA-CS复合支架对细胞的影响。该混合HA-CS复合支架不仅支持hBMSCs的黏附和增殖，还提高了骨诱导性。混合HA-CS复合支架上的碱性磷酸酶活性和矿化沉积高于CS纤维多孔支架。此外，与CS纤维多孔支架相比，混合HA-CS复合支架可促进大鼠颅骨缺损处新骨的形成。优异的生物相容性、骨诱导性和力学性能表明，该混合纳米结构的HA-CS复合支架在骨组织工程中具有巨大潜力。
