Development of regenerative therapy for jaw bone using scaffold with carbon nanotubes.

本研究通过对碳纳米管（CNTs）生物相容性的研究、CNTs支架上细胞的培养以及CNTs块体的制备，将CNTs植入大鼠皮下组织2年，并进行组织学和超微结构观察。在巨噬细胞的溶酶体中观察到一些CNT，并且在2年时仅在CNT周围识别出轻微的肉芽肿性炎症反应，尽管在植入后的早期阶段在CNT周围观察到具有吞噬细胞的肉芽组织。随着时间的延长，碳纳米管的聚集程度逐渐变小。通过使用TEM观察，在2年后，大多数CNT样管的典型结构没有改变。结果表明，CNTs在体内不是强前体物质，其晶体结构稳定。将分散好的CNTs浆料真空抽滤到聚碳酸酯（PC）膜上，制成CNTs支架。在支架上培养人成骨样细胞Saos-2。Saos-2在碳纳米管支架上的增殖能力和碱性磷酸酶活性均高于PC膜。与PC膜相比，CNTs支架引导骨再生膜应用于大鼠顶骨骨缺损的成骨效果更好。块体碳纳米管的物理力学性能接近骨的物理力学性能，生物相容性良好。这些结果表明，SPS法制备的碳纳米管块体材料适合作为骨替代材料，从而为利用碳纳米管进行颌骨再生治疗提供了可能。

In this study, investigation of biocompatibility of carbon nanotubes (CNTs), cell culture on the scaffold using with CNTs and fabrication of bulk CNTs were carried out for the purpose of reconstruction of jaw bone using with CNTs.CNTs were implanted in the subcutaneous tissue in rats for 2 years, and histological and ultramicrostructural investigation to CNTs were done. Some CNTs were observed in lysosome in macrophages and only slight granulomatous inflammatory response was recognized around CNTs at 2 years, although granulation tissue with phagocytes was seen around CNTs at early stage after implant. The degree of aggregation of CNTs became to slight with time. Most of typical structure of CNTs like tubes was not changed after 2 years by observation using TEM. These results suggested that CNTs was not strong prophlogistic substance and structure of crystal of CNTs was stable in vivo.Scaffolds with CNTs were made by vacuum filtration of the dispersed CNTs slurry onto polycarbonate (PC) membrane. Saos-2 (human osteoblast-like cell) was cultured on the scaffolds. Proliferation and alkaline phosphatase activity of Saos-2 cultured on the CNTs scaffolds were higher than those of PC membrane. Application of the CNTs scaffold for guided bone regeneration membrane to bone defects made on rat parietal bone was effective in osteogenesis compared to PC membrane.Bulk CNTs materials were fabricated by spark plasma sintering (SPS). Physical and mechanical properties of bulk CNTs were close to those of bone, and biocompatibility was excellent. These results showed that bulk CNTs made by SPS method was suitable for bone substitute materials.From these results, it was suggested that regenerative therapy for jaw bone using with CNTs would be possible.