McManus Anastasia J, Doremus Robert H, Siegel Richard W, Bizios Rena
Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA.
J Biomed Mater Res A. 2005 Jan 1;72(1):98-106. doi: 10.1002/jbm.a.30204.
In an attempt to simulate the microstructure and mechanical properties of natural bone, novel nanoceramic/polymer composite formulations were fabricated and characterized with respect to their cytocompatibility and mechanical properties. The bending moduli of nanocomposite samples of either poly(L-lactic acid) (PLA) or poly(methyl methacrylate) (PMMA) with 30, 40, and 50 wt % of nanophase (<100 nm) alumina, hydroxyapatite, or titania loadings were significantly (p < 0.05) greater than those of pertinent composite formulations with conventional, coarser grained ceramics. The nanocomposite bending moduli were 1-2 orders of magnitude larger than those of the homogeneous, respective polymer. For example, compared with 0.06 GPa for the 100% PLA, the bending modulus of 50/50 nanophase alumina/PLA composites was 3.5 GPa. Osteoblast adhesion on the surfaces of the nanophase alumina/PLA composites increased as a function of the nanophase ceramic content. Most importantly, osteoblast adhesion on the 50/50 nanophase alumina/PLA substrates was similar to that observed on the 100% nanophase ceramic substrates. Similar trends of osteoblast adhesion were observed on the surfaces of the nanophase titania/polymer and nanophase hydroxyapaptite/polymer composites that were tested. In contrast, fibroblast adhesion on the nanophase composites was either similar or lower than that observed on the conventional composites with either PLA or PMMA and minimum on all tested neat nanophase substrates. The calcium content in the extracellular matrix of cultured osteoblasts was also enhanced on the nanoceramic/PLA composite substrates tested as a function of the nanophase ceramic loading and duration of cell culture. The results of the present in vitro study provide evidence that nanoceramic/polymer composite formulations are promising alternatives to conventional materials because they can potentially be designed to match the chemical, structural, and mechanical properties of bone tissue in order to overcome the limitations of the biomaterials currently used as bone prostheses.
为了模拟天然骨的微观结构和力学性能，制备了新型纳米陶瓷/聚合物复合配方，并对其细胞相容性和力学性能进行了表征。聚（L-乳酸）（PLA）或聚甲基丙烯酸甲酯（PMMA）与30%、40%和50%重量百分比的纳米相（<100nm）氧化铝、羟基磷灰石或二氧化钛负载的纳米复合样品的弯曲模量显著（p<0.05）高于具有传统粗晶陶瓷的相关复合配方。纳米复合弯曲模量比相应的均相聚合物大1-2个数量级。例如，与100%PLA的0.06GPa相比，50/50纳米相氧化铝/PLA复合材料的弯曲模量为3.5GPa。成骨细胞在纳米相氧化铝/PLA复合材料表面的粘附随着纳米相陶瓷含量的增加而增加。最重要的是，在50/50纳米相氧化铝/PLA基底上的成骨细胞粘附与在100%纳米相陶瓷基底上观察到的相似。在测试的纳米相二氧化钛/聚合物和纳米相羟基磷灰石/聚合物复合材料表面也观察到类似的成骨细胞粘附趋势。相比之下，成纤维细胞在纳米相复合材料上的粘附与在含PLA或PMMA的传统复合材料上观察到的相似或更低，并且在所有测试的纯纳米相基底上最低。在测试的纳米陶瓷/PLA复合基底上，培养的成骨细胞细胞外基质中的钙含量也随着纳米相陶瓷负载量和细胞培养时间的增加而增加。本体外研究结果提供了证据，表明纳米陶瓷/聚合物复合配方是传统材料的有前途的替代品，因为它们有可能被设计成匹配骨组织的化学、结构和力学性能，以克服目前用作骨假体的生物材料的局限性。
