A biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties and accelerating osseointegration in spinal fusion

• Published in: Bioactive materials Vol. 23; pp. 234 - 246
• Main Authors: Jia, Cheng-Qi, Zhang, Zhen, Cao, Shi-Qi, Wang, Tian-Jiao, Yu, Hai-Chao, Wang, Wen-Xiang, Guo, Bo-Min, Qiu, Xiong-Ying, You, Yong-Gang, Hu, Fan-Qi, Zhao, Jun, Zhang, Xue-Song
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2023; KeAi Communications Co., Ltd
• Subjects: Biomimetic; Composite; Osseointegration; Porous; Spinal fusion; Osseointegration; Biomimetic; Composite; Porous; Spinal fusion
• ISSN: 2452-199X; 2452-199X
• DOI: 10.1016/j.bioactmat.2022.11.003

Spinal fusion is a widely employed treatment of patients with degenerative disc disease, in which a cage is used to replace the disc for spinal fusion. But it often fails for insufficient mechanical strength and poor osseointegration. Here, we designed a polyether-ether-ketone (PEEK)/tantalum (Ta) composite cage with a biomimetic gradient porous micro-structure, simultaneously enhancing mechanical properties and accelerating osseointegration in spinal fusion. In the study, based on the mechanical performances of PEEK and osteogenic potential of Ta, and the three-dimensional (3D) structures of cuttlebone and vertebra, the cages were respectively 3D printed by pure PEEK, PEEK with 5 wt% Ta (PEEK/Ta-5), PEEK with 10 wt% Ta (PEEK/Ta-10) and PEEK with 15 wt% Ta (PEEK/Ta-15), then verified in vitro and in sheep cervical fusion model systematically. Vertebral Gyroid structure PEEK/Ta-15 cage exhibited superior mechanical properties than Cuttlebone-like structure PEEK/Ta-15 cage, closer to the cervical vertebra. Furthermore, PEEK/Ta-15 cage with higher Ta microparticles in PEEK provided a biomimetic gradient porous micro-structure with higher surface energy, guiding cell biological behavior, promoting new bone penetration, and accelerating osseointegration in vivo . In conclusion, the study designed a biomimetic gradient porous cage with a micro-structure for enhancing mechanical properties, accelerating osseointegration and forming an anatomical lock in the fusion segment through composites, mechanical efficiency, surface extension, and pores. [Display omitted] •3D printed PEEK/Ta composites bioinspired structures.•The mechanics of PEEK/Ta Cuttlebone-like and Gyroid porous structures.•A micro-structure of PEEK/Ta cages for guiding cell biological behavior.•Sheep cervical fusion model for biomechanics of PEEK/Ta cages.