Lu S, McEnery M A P, Rogers B R, Wenke J C, Shimko D, Guelcher S A
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
J Mater Chem B. 2017 Jun 14;5(22):4198-4206. doi: 10.1039/c7tb00657h. Epub 2017 May 11.
Bone cements for treatment of fractures at weight-bearing sites are subjected to dynamic physiological loading from daily activities. An ideal bone cement rapidly sets after injection, exhibits bone-like strength, stimulates osteogenic differentiation of endogenous cells, and resorbs at a rate aligned with patient biology. However, currently available materials fall short of these targeted properties. Nanocrystalline hydroxyapatite (nHA) enhances osteogenic differentiation, new bone formation, and osteoclast differentiation activity compared to amorphous or micron-scale crystalline hydroxyapatite. However, the brittle mechanical properties of nHA precludes its use in treatment of weight-bearing bone defects. In this study, we report settable nHA-poly(ester urethane) (PEUR) nanocomposites synthesized from nHA, lysine triisocyanate (LTI), and poly(caprolactone) triol via a solvent-free process. The nanocomposites are easily mixed and injected using a double-barrel syringe, exhibit mechanical properties exceeding those of conventional bone cements, enhance mineralization of osteoprogenitor cells in vitro, and undergo osteoclast-mediated degradation in vitro. This combination of properties cannot be achieved using other technologies, which underscores the potential of nHA-PEUR nanocomposites as a new approach for promoting bone healing at weight-bearing sites.
用于治疗负重部位骨折的骨水泥会受到日常活动产生的动态生理负荷。理想的骨水泥在注射后能迅速凝固，具有类似骨的强度，刺激内源性细胞的成骨分化，并以与患者生理状况相匹配的速率进行吸收。然而，目前可用的材料未能达到这些目标特性。与无定形或微米级结晶羟基磷灰石相比，纳米晶羟基磷灰石（nHA）能增强成骨分化、新骨形成和破骨细胞分化活性。然而，nHA的脆性机械性能使其无法用于治疗负重骨缺损。在本研究中，我们报告了通过无溶剂工艺由nHA、赖氨酸三异氰酸酯（LTI）和聚己内酯三醇合成的可凝固nHA-聚（酯脲）（PEUR）纳米复合材料。这些纳米复合材料使用双筒注射器易于混合和注射，其机械性能超过传统骨水泥，在体外增强成骨祖细胞的矿化，并在体外经历破骨细胞介导的降解。使用其他技术无法实现这种性能组合，这突出了nHA-PEUR纳米复合材料作为促进负重部位骨愈合新方法的潜力。
