Biomaterial Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran 1591634311, Iran.
Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
ACS Biomater Sci Eng. 2020 May 11;6(5):2985-2994. doi: 10.1021/acsbiomaterials.9b01789. Epub 2020 Apr 6.
Hypoxia, the result of disrupted vasculature, can be categorized in the main limiting factors for fracture healing. A lack of oxygen can cause cell apoptosis, tissue necrosis, and late tissue healing. Remedying hypoxia by supplying additional oxygen will majorly accelerate bone healing. In this study, biphasic calcium phosphate (BCP) scaffolds were fabricated by robocasting, an additive manufacturing technique. Then, calcium peroxide (CPO) particles, as an oxygen-releasing agent, were coated on the BCP scaffolds. Segmental radial defects with the size of 15 mm were created in rabbits. Uncoated and CPO-coated BCP scaffolds were implanted in the defects. The empty (control) group received no implantation. Repairing of the bone was investigated via X-ray, histological analysis, and biomechanical tests at 3 and 6 months postoperatively, with immunohistochemical examinations at 6 months after operation. According to the radiological observations, formation of new bone was augmented at the interface between the implant and host bone and internal pores of CPO-coated BCP scaffolds compared to uncoated scaffolds. Histomorphometry analysis represented that the amount of newly formed bone in the CPO-coated scaffold was nearly two times higher than the uncoated one. Immunofluorescence staining revealed that osteogenic markers, osteonectin and octeocalcin, were overexpressed in the defects treated with the coated scaffolds at 6 months of postsurgery, demonstrating higher osteogenic differentiation and bone mineralization compared to the uncoated scaffold group. Furthermore, the coated scaffolds had superior biomechanical properties as in the case of 3 months after surgery, the maximal flexural force of the coated scaffolds reached to 134 N, while it was 92 N for uncoated scaffolds. The results could assure a boosted ability of bone repair for CPO-coated BCP scaffolds implanted in the segmental defect of rabbit radius because of oxygen-releasing coating, and this system of oxygen-generating coating/scaffold might be a potential for accelerated repairing of bone defects.
缺氧是血管紊乱的结果，可归类为骨折愈合的主要限制因素。缺氧会导致细胞凋亡、组织坏死和晚期组织愈合。通过提供额外的氧气来纠正缺氧，将极大地加速骨骼愈合。在这项研究中，通过增材制造技术——机器人铸造技术来制造双相磷酸钙（BCP）支架。然后，将过氧钙（CPO）颗粒作为一种释氧剂涂覆在 BCP 支架上。在兔子身上制造大小为 15 毫米的节段性桡骨缺损。将未涂层和 CPO 涂层的 BCP 支架植入缺损部位。空（对照）组未进行植入。通过 X 射线、组织学分析和术后 3 个月和 6 个月的生物力学测试以及术后 6 个月的免疫组织化学检查来研究骨修复情况。根据影像学观察，与未涂层支架相比，CPO 涂层 BCP 支架的植入物与宿主骨之间的界面和内部孔隙处形成了更多的新骨。组织形态计量学分析表明，CPO 涂层支架中新形成的骨量几乎是未涂层支架的两倍。免疫荧光染色显示，在术后 6 个月，用涂层支架处理的缺损中，成骨标志物骨粘连蛋白和骨钙素过度表达，表明与未涂层支架组相比，成骨分化和骨矿化程度更高。此外，涂层支架具有更好的生物力学性能，例如在术后 3 个月时，涂层支架的最大弯曲力达到 134N，而未涂层支架的最大弯曲力为 92N。这些结果可以确保 CPO 涂层 BCP 支架在兔桡骨节段性缺损中植入时具有增强的骨修复能力，因为该释氧涂层系统可能是加速骨缺损修复的潜在方法。
