【作者】 潘兰兰； 向学熔； 李晓东；

【机构】 重庆医科大学附属口腔医院牙周科； 重庆医科大学附属口腔医院VIP科室；

【摘要】 结合超声分散技术,以液相共混法制备出多壁碳纳米管/聚己内酯(MWNTs/PCL)复合材料,并研究了不同碳纳米管浓度(按MWNTs/PCL的质量比分别为0%、0.25%、0.5%、1%、2%五组)的复合材料的物理学性能、体内成骨的研究,以探索其在骨组织工程应用的可能性。通过扫描电镜(SEM)及原子力显微镜(AFM)分析复合材料的形貌和结构组成进行表征以及热重量分析(TGA)以了解碳纳米管的添加对PCL热学性能的影响。将各组材料浸泡在磷酸盐缓冲溶液(PBS)中进行体外降解研究,根据各组材料降解液的p H值、材料的失重及压缩模量的变化,分析和评价是否符合植入材料的要求;在此基础上对各组材料进行体外仿生矿化的研究,分析其生物活性、观察材料表面磷灰石晶体的形成,对矿化材料的表面形貌和结构组成进行表征;将各组复合材料植入SD大鼠股骨的缺损处,修复实验性骨缺损,采用MicroCT观察复合材料在体内骨缺损处的结合情况,评价其缺损修复能力;采用组织切片法(HE染色和Masson染色)对复合材料生物相容性进行体内评价。实验结果表明,.经过超声处理后,MWNTs能均匀地分散于PCL基质中,并呈不同方向凸显于材料表面。MWNTs的加入并没有显著影响到聚己内酯的晶相结构。体外降解实验中,得知MWNTs/PCL复合材料中的PCL仍然保存着纯PCL的降解性能,但是由于碳纳米管的加入,复合材料在此降解期间的力学性能均高于纯PCL。SEM结果显示复合材料在浸入SBF 7天后即在其表面均可见类骨羟磷灰石的形成。并且随着时间的增长羟磷灰石的晶体从小变大,越来越致密。.体内实验结果从Micro CT的数据分析来看MWNTs/PCL复合材料比纯PCL能更好地在体内诱导新骨形成。从组织学结果来看,复合材料的植入并未见炎性细胞侵入,且材料周围有骨胶原纤维生成。进而表明MWNTs/PCL复合材料和宿主骨之间很好的生物相容性和骨诱导性。因此,MWNTs的添加提高了复合材料的力学性能,在体外矿化实验中能在其表面形成类骨羟基磷灰石。MWNTs/PCL复合材料具有良好的生物相容性,并能在体内诱导成骨。MWNTs/PCL复合材料具有在骨组织工程中应用潜能。更多还原

【Abstract】 For bone regeneration,scaffolds are typically made of degradable and biocompatible materials that provide mechanical support and promote bone formation during repair and regeneration of damaged bone.In this work,the multiwalled carbon nanotubes(MWNTs)/polycaprolactone(PCL) composite scaffolds were fabricated via the solution evaporation technique.The surface topography of the composite scaffolds was examined by scanning electron microscopy(SEM) and atomic force microscopy(AFM).The influence of MWNTs on the thermal stability of the composites was investigated by thermogravimetric analysis(TGA).The in vitro degradation was characterized in terms of the decrease of pH value of degradation media,the weight loss as well as the compressive modulus of PCL ant its composites.The biomimetic mineralization of hydroxyapatite(HA) on the surface of composite scaffolds was used to predict their in vivo bone bioactivity.The in vivo biocompatibility and osteogenesis of MWNTs/PCL composites were further studied on rats with femur bone defects radiographically and histologically.The results showed that the added MWNTs(0.25-2.0 wt %) improved the mechanical and thermal properties of composite scaffolds and imposed little effects on PCL’s biodegradability.In addition,the MWNTs/PCL composite scaffolds showed good in vivo biocompatible and osteogenesis properties,and the composite with 0.5 wt % MWNTs induced better cell proliferation and promoted new bone formation with higher bone density and bone regeneration efficacy.Therefore,the MWNTs/PCL scaffold,with advanced structural,mechanical and biological properties,might be a suitable candidate for bone tissue engineering applications.更多还原