Shenzhen Key Laboratory for Innovative Technology in Orthopedic Trauma, Department of Orthopaedics and Traumatology, The University of Hong Kong-Shenzhen Hospital, Shenzhen 518053, PR China.
Medical Research Institute, Department of Orthopedics, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, PR China; Hebei Key Laboratory of Biomaterials and Smart Theranostics, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, PR China.
Colloids Surf B Biointerfaces. 2024 Apr;236:113805. doi: 10.1016/j.colsurfb.2024.113805. Epub 2024 Feb 17.
Bone implantation inevitably causes damage to surrounding vasculature, resulting in a hypoxic microenvironment that hinders bone regeneration. Although titanium (Ti)-based devices are widely used as bone implants, their inherent bioinert surface leads to poor osteointegration. Herein, a strontium peroxide (SrO)-decorated Ti implant, Ti_P@SrO, was constructed through coating with poly-L-lactic acid (PLLA) to alleviate the hypoxic microenvironment and transform the bioinert surface of the implant into a bioactive surface. PLLA degradation resulted in an acidic microenvironment and the release of SrO nanoparticles. The acidic microenvironment then accelerated the decomposition of SrO, resulting in the release of O and Sr ions. O released from Ti_P@SrO can alleviate the hypoxic microenvironment, thus enhancing cell proliferation in an O-insufficient microenvironment. Furthermore, under hypoxic and normal microenvironments, Ti_P@SrO enhanced alkaline phosphatase activity and bone-related gene expression in C3H10T1/2 cells with the continuous release of Sr ions. Meanwhile, Ti_P@SrO suppressed M1 polarization and promoted M2 polarization of bone marrow-derived monocytes under hypoxic and normal conditions. Furthermore, in a rat implantation model, the implant enhanced new bone formation and improved osteointegration after modification with SrO. In summary, the newly designed O- and Sr ion-releasing Ti implants are promising for applications in bone defects.
骨植入物不可避免地会对周围的脉管系统造成损伤，导致缺氧的微环境，从而阻碍骨再生。尽管钛（Ti）基设备广泛用作骨植入物，但它们固有的生物惰性表面导致骨整合不良。在此，通过聚 L-乳酸（PLLA）涂层构建了过氧锶（SrO）修饰的 Ti 植入物 Ti_P@SrO，以减轻缺氧微环境并将植入物的生物惰性表面转化为生物活性表面。PLLA 降解导致酸性微环境和 SrO 纳米粒子的释放。然后，酸性微环境加速 SrO 的分解，导致 O 和 Sr 离子的释放。Ti_P@SrO 释放的 O 可以缓解缺氧微环境，从而增强 O 不足微环境中的细胞增殖。此外，在缺氧和正常微环境下，Ti_P@SrO 通过持续释放 Sr 离子，增强 C3H10T1/2 细胞中碱性磷酸酶活性和与骨相关的基因表达。同时，Ti_P@SrO 在缺氧和正常条件下抑制骨髓来源单核细胞的 M1 极化并促进 M2 极化。此外，在大鼠植入模型中，经 SrO 修饰后，植入物增强了新骨形成并改善了骨整合。总之，新设计的 O 和 Sr 离子释放 Ti 植入物有望应用于骨缺损。
