Key Lab of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, China.
Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, School of Mechanical Engineering, Tianjin University, Tianjin, 300354, China.
Adv Healthc Mater. 2019 Nov;8(22):e1901103. doi: 10.1002/adhm.201901103. Epub 2019 Oct 14.
Repairing osteochondral defects is a considerable challenge because it involves the breakdown of articular cartilage and underlying bone. Traditional hydrogels with a homogenized single-layer structure cannot fully restore the function of osteochondral cartilage tissue. In this study, a mussel-inspired hydrogel with a bilayer structure is developed to repair osteochondral defects. The hydrogel is synthesized by simultaneously polymerizing two layers using a one-pot method. The resulting upper and lower gelatin methacryloyl-polydopamine hydrogel layers are used as cartilage and subchondral bone repair layers, respectively. Polydopamine-induced hydroxyapatite in situ mineralization takes place in the lower layer to mimic the structure of subchondral bone. The bilayer hydrogel exhibits good mechanical properties for the synergistic effect of covalent and noncovalent bonds, as well as nanoreinforcement of mineralized hydroxyapatite. To improve the tissue-inducibility of hydrogels, transforming growth factor β is immobilized in the upper layer to induce cartilage regeneration, while bone morphogenetic protein 2 is immobilized in the lower layer to induce bone regeneration. Bone and cartilage repair performance of the hydrogel is examined by implantation into a full-thickness cartilage defect of a rabbit knee joint. The bilayer-structure hydrogel promotes regeneration of osteochondral tissue, thus providing a new option for repair of osteochondral defects.
修复骨软骨缺损是一项重大挑战，因为它涉及到关节软骨和下面的骨的破坏。具有均匀单层结构的传统水凝胶不能完全恢复骨软骨组织的功能。在这项研究中，开发了一种具有双层结构的贻贝启发的水凝胶来修复骨软骨缺损。该水凝胶是通过一锅法同时聚合两层合成的。所得的上层和下层明胶甲基丙烯酰化-聚多巴胺水凝胶层分别用作软骨和软骨下骨修复层。聚多巴胺诱导的原位羟基磷灰石矿化发生在下层，以模拟软骨下骨的结构。双层水凝胶具有良好的机械性能，这是由于共价和非共价键的协同作用以及矿化羟基磷灰石的纳米增强作用。为了提高水凝胶的组织诱导性，将转化生长因子β固定在上层以诱导软骨再生，而将骨形态发生蛋白 2 固定在下层以诱导骨再生。通过将水凝胶植入兔膝关节全层软骨缺损来检查其骨软骨修复性能。双层结构水凝胶促进骨软骨组织的再生，为骨软骨缺损的修复提供了新的选择。
