Jiao Xiaoyi, Wu Fanghui, Yue Xusong, Yang Jun, Zhang Yan, Qiu Jiandi, Ke Xiurong, Sun Xiaoliang, Zhao Liben, Xu Chuchu, Li Yifan, Yang Xianyan, Yang Guojing, Gou Zhongru, Zhang Lei
Department of Orthopaedic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China.
Department of Orthopaedics, The Third Hospital Affiliated to Wenzhou Medical University & Rui'an People's Hospital, Rui'an, 325200, China.
Mater Today Bio. 2023 Dec 28;24:100936. doi: 10.1016/j.mtbio.2023.100936. eCollection 2024 Feb.
Structural parameters of the implants such as shape, size, and porosity of the pores have been extensively investigated to promote bone tissue repair, however, it is unknown how the pore interconnectivity affects the bone growth behaviors in the scaffolds. Herein we systematically evaluated the effect of biodegradable bioceramics as a secondary phase filler in the macroporous networks on the mechanical and osteogenic behaviors in sparingly dissolvable bioceramic scaffolds. The pure hardystonite (HT) scaffolds with ∼550 & 800 μm in pore sizes were prepared by digital light processing, and then the Sr-doped calcium silicate (SrCSi) bioceramic slurry without and with 30 % organic porogens were intruded into the HT scaffolds with 800 μm pore size and sintered at 1150 °C. It indicated that the organic porogens could endow spherical micropores in the SrCSi filler, and the invasion of the SrCSi component could not only significantly enhance the compressive strength and modulus of the HT-based scaffolds, but also induce osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The pure HT scaffolds showed extremely slow bio-dissolution in Tris buffer after immersion for 8 weeks (∼1 % mass decay); in contrast, the SrCSi filler would readily dissolve into the aqueous medium and produced a steady mass decay (>6 % mass loss). experiments in rabbit femoral bone defect models showed that the pure HT scaffolds showed bone tissue ingrowth but the bone growth was impeded in the SrCSi-intruded scaffolds within 4 weeks; however, the group with higher porosity of SrCSi filler showed appreciable osteogenesis after 8 weeks of implantation and the whole scaffold was uniformly covered by new bone tissues after 16 weeks. These findings provide some new insights that the pore interconnectivity is not inevitable to impede bone ingrowth with the prolongation of implantation time, and such a highly biodegradable and bioactive filler intrusion strategy may be beneficial for optimizing the performances of scaffolds in bone regenerative medicine applications.
为促进骨组织修复，人们对植入物的结构参数如形状、尺寸和孔隙率进行了广泛研究，然而，孔隙的连通性如何影响支架中的骨生长行为尚不清楚。在此，我们系统地评估了可生物降解生物陶瓷作为大孔网络中的第二相填料对微溶性生物陶瓷支架的力学和骨生成行为的影响。通过数字光处理制备了孔径约为550和800μm的纯硬硅钙石（HT）支架，然后将不含和含有30%有机致孔剂的掺锶硅酸钙（SrCSi）生物陶瓷浆料注入孔径为800μm的HT支架中，并在1150℃下烧结。结果表明，有机致孔剂可在SrCSi填料中形成球形微孔，SrCSi组分的侵入不仅能显著提高HT基支架的抗压强度和模量，还能诱导骨髓间充质干细胞（BMSC）的成骨分化。纯HT支架在Tris缓冲液中浸泡8周后生物溶解极慢（质量衰减约1%）；相比之下，SrCSi填料很容易溶解到水介质中并产生稳定的质量衰减（质量损失>6%）。在兔股骨骨缺损模型中的实验表明，纯HT支架有骨组织长入，但在4周内，SrCSi侵入的支架中的骨生长受到阻碍；然而，SrCSi填料孔隙率较高的组在植入8周后显示出明显的成骨作用，16周后整个支架被新骨组织均匀覆盖。这些发现提供了一些新的见解，即随着植入时间的延长，孔隙连通性并非必然阻碍骨长入，这种高度可生物降解和生物活性的填料侵入策略可能有利于优化骨再生医学应用中支架的性能。
