The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China; CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia; Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237, PR China.
CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168, Australia.
Biomaterials. 2014 Mar;35(9):2730-42. doi: 10.1016/j.biomaterials.2013.12.028. Epub 2014 Jan 15.
Although rhBMP-2 has excellent ability to accelerate the repair of normal bone defects, limitations of its application exist in the high cost and potential side effects. This study aimed to develop a composite photopolymerisable hydrogel incorporating rhBMP-2 loaded 2-N, 6-O-sulfated chitosan nanoparticles (PH/rhBMP-2/NPs) as the bone substitute to realize segmental bone defect repair at a low growth factor dose. Firstly rhBMP-2 loaded 2-N, 6-O-sulfated chitosan nanoparticles (rhBMP-2/NPs) were prepared and characterized by DLS and TEM. Composite materials, PH/rhBMP-2/NPs were developed and investigated by SEM-EDS as well as a series of physical characterizations. Using hMSCs as an in vitro cell model, composite photopolymerisable hydrogels incorporating NPs (PH/NPs) showed good cell viability, cell adhesion and time dependent cell ingrowth. In vitro release kinetics of rhBMP-2 showed a significantly lower initial burst release from the composite system compared with the growth factor-loaded particles alone or encapsulated directly within the hydrogel, followed by a slow release over time. The bioactivity of released rhBMP-2 was validated by alkaline phosphatase (ALP) activity as well as a mineralization assay. In in vivo studies, the PH/rhBMP-2/NPs induced ectopic bone formation in the mouse thigh. In addition, we further investigated the in vivo effects of rhBMP-2-loaded scaffolds in a rabbit radius critical defect by three dimensional micro-computed tomographic (μCT) imaging, histological analysis, and biomechanical measurements. Animals implanted with the composite hydrogel containing rhBMP-2-loaded nanoparticles underwent gradual resorption with more pronounced replacement by new bone and induced reunion of the bone marrow cavity at 12 weeks, compared with animals implanted with hydrogel encapsulated growth factors alone. These data provided strong evidence that the composite PH/rhBMP-2/NPs are a promising substitute for bone tissue engineering.
尽管 rhBMP-2 具有出色的加速修复正常骨缺损的能力，但它的应用存在局限性，即成本高和潜在的副作用。本研究旨在开发一种复合光聚合水凝胶，其中包含负载 rhBMP-2 的 2-N,6-O-磺化壳聚糖纳米颗粒（PH/rhBMP-2/NPs）作为骨替代物，以实现低生长因子剂量的节段性骨缺损修复。首先，通过 DLS 和 TEM 制备并表征负载 rhBMP-2 的 2-N,6-O-磺化壳聚糖纳米颗粒（rhBMP-2/NPs）。通过 SEM-EDS 以及一系列物理特性研究来开发和研究复合材料 PH/rhBMP-2/NPs。使用 hMSCs 作为体外细胞模型，负载纳米颗粒的复合光聚合水凝胶（PH/NPs）表现出良好的细胞活力、细胞黏附和时间依赖性细胞向内生长。rhBMP-2 的体外释放动力学表明，与单独负载生长因子的颗粒或直接包封在水凝胶中的颗粒相比，复合体系的初始突释释放显著降低，随后随时间缓慢释放。释放的 rhBMP-2 的生物活性通过碱性磷酸酶（ALP）活性和矿化测定来验证。在体内研究中，PH/rhBMP-2/NPs 在小鼠大腿中诱导异位骨形成。此外，我们还通过三维微计算机断层扫描（μCT）成像、组织学分析和生物力学测量，进一步研究了 rhBMP-2 负载支架在兔桡骨临界缺损中的体内效应。与单独包封生长因子的水凝胶相比，植入含有负载 rhBMP-2 的纳米颗粒的复合水凝胶的动物经历了逐渐吸收，更多的新骨替代，并且在 12 周时骨髓腔重新融合。这些数据为负载 rhBMP-2 的复合 PH/rhBMP-2/NPs 是骨组织工程的一种有前途的替代物提供了有力证据。
