State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China.
J Mater Chem B. 2024 Nov 6;12(43):11187-11201. doi: 10.1039/d4tb01923g.
In bone tissue, nerves are primarily located in the periosteum and play an indispensable role in bone defect repair. However, most bone tissue engineering approaches ignored the reconstruction of the nerve network. Herein, we aimed to develop a bilayer hydrogel simulating periosteum-bone structure to induce innervated bone regeneration. The bottom "bone" layer consisted of gelatin methacryloyl (GelMA), poly(ethylene glycol) diacrylate (PEGDA), and nano-hydroxyapatite (nHA), whereas the upper "periosteum" layer consisted of GelMA, sodium alginate (SA) and MgCl. The mechanical properties of the upper and bottom hydrogels were designed to be suitable for neurogenesis and osteogenesis, respectively. Besides, Mg from the "periosteum" layer released at the early stage (within 7 d), which aligned with the optimal time window for nerve regeneration and osteogenic related neuropeptide release. Simultaneously, the prevention of long-term Mg release (after 7 d) could avoid osteogenic inhibition caused by prolonged Mg exposure. Additionally, the incorporation of nHA in the bottom "bone" layer supported the long-term osteogenesis due to its osteoconductivity and slow degradation. biological experiments revealed that the bilayer hydrogel (GS@Mg/GP@nHA) promoted neurite growth and calcitonin gene-related peptide (CGRP) expression in rat dorsal root ganglion (DRG) neurons, as well as the osteogenesis of rat bone-derived mesenchymal stem cells (BMSCs). Moreover, the experiments demonstrated that the GS@Mg/GP@nHA hydrogel efficiently promoted nerve network reconstruction and bone regeneration of rat calvarial bone defects. Altogether, the bilayer hydrogel GS@Mg/GP@nHA could promote innervated bone regeneration, providing new insights for biomaterial design for bone tissue engineering.
在骨组织中，神经主要位于骨膜中，在骨缺损修复中起着不可或缺的作用。然而，大多数骨组织工程方法忽略了神经网络的重建。在此，我们旨在开发一种模拟骨膜-骨结构的双层水凝胶来诱导神经支配的骨再生。底层“骨”层由明胶甲基丙烯酰（GelMA）、聚乙二醇二丙烯酸酯（PEGDA）和纳米羟基磷灰石（nHA）组成，而上层“骨膜”层由 GelMA、海藻酸钠（SA）和 MgCl 组成。上、下水凝胶的机械性能分别设计为适合神经发生和成骨。此外，“骨膜”层中的 Mg 在早期（7 天内）释放，这与神经再生和成骨相关神经肽释放的最佳时间窗口一致。同时，避免 Mg 的长期释放（7 天后）可以避免由于长时间暴露于 Mg 而导致的成骨抑制。此外，底部“骨”层中 nHA 的掺入由于其骨传导性和缓慢降解而支持长期成骨。生物学实验表明，双层水凝胶（GS@Mg/GP@nHA）促进了大鼠背根神经节（DRG）神经元的神经突生长和降钙素基因相关肽（CGRP）表达，以及大鼠骨髓间充质干细胞（BMSCs）的成骨作用。此外，实验表明，GS@Mg/GP@nHA 水凝胶有效地促进了大鼠颅骨骨缺损的神经网络重建和骨再生。总的来说，双层水凝胶 GS@Mg/GP@nHA 可以促进神经支配的骨再生，为骨组织工程的生物材料设计提供了新的思路。
