改良低温机械物理研磨法制备纳米脱钙骨基质

Preparation of nano-demineralized bone matrix by modified low temperature mechanical trituration

背景:前期研究证实纳米脱钙骨基质为一种无毒、组织相容性良好、生物利用度高、炎症反应轻、成骨能力强的骨移植替代物,但其制备耗时较长,需多次间断取样行粒度分析,研磨效率低。目的:采用低温物理研磨法制备纳米脱钙骨基质,分析纳米脱钙骨基质的结构特征及制备效率。方法:采用改良Urist法制备同种异体脱钙骨基质,通过二次低温物理研磨法,应用CryoMill全自动冷冻研磨仪先将脱钙骨基质初步研磨至微米级别颗粒,再通过E-Max高能水冷球磨仪进行纳米尺度研磨,最后通过扫描电镜观测研磨效果及材料形貌。结果与结论:采用二次低温物理研磨法制备的纳米脱钙骨基质底层致密,表面充满不规则纳米颗粒,颗粒直径20-50nm,纳米颗粒相互团聚,表面密布纳米级别凹槽,纳米纤维结构间相互连接,内部形成大量相互连通的微米级别孔隙,其微观结构符合纳米生物材料范畴;二次低温物理研磨法仅需25min,提高了研磨效率;结果说明,二次低温物理研磨法制备纳米脱钙骨基质的研磨结果更确切、材料粒度分布均匀性更高。

BACKGROUND: Previous studies have confirmed that nano-demineralized bone matrix is an alternative to an autograft with non-toxicity, good tissue compatibility, high bioavailability, mild inflammatory reaction, strong osteogenic ability. But its preparation takes long time. Intermittent sampling is required for particle size analysis. OBJECTIVE: To prepare nano-demineralized bone matrix by low temperature mechanical trituration and analyze its structure characteristics and preparation efficacy. METHODS: Allogeneic decalcified bone matrix was prepared by the modified Urist method. The CryoMill automatic freezing grinder was used to initially grind the decalcified bone matrix to the micron-sized particles. Then the E-Max high-energy water-cooled ball mill was used to grind the micro-sized particles into nano-sized particles. Finally, the grinding effect and material appearance were observed by scanning electron microscopy. RESULTS AND CONCLUSION: After two-step grinding, the prepared decalcified bone matrix had nanostructure composed by irregular 20-50 nm-sized nanoparticles through agglomeration. The surface of nano-particles was densely covered with nano-scale grooves. A large number of interconnected micro-pores formed between nanofiber structures, the microstructure of which conformed to the category of nanobiomaterials. Compared with the Micro superfine mill, the new trituration process only took 25 minutes, which increases grinding efficacy. These results suggest that two steps of low temperature mechanical trituration for preparation of nano-demineralized bone matrix produces more uniform particle size distribution.