胶原/二氧化硅纳米微粒构建神经支架物理特性研究

Characterization of collagen/silica composite scaffolds for peripheral nerve regeneration

目的 观察胶原复合二氧化硅纳米微粒在构建组织工程化神经支架中的作用.方法 利用冻干技术掺入不同浓度分别为5、10、25、50、100 μg/ml二氧化硅纳米微粒制作多孔胶原支架,相同方法制备单一的不含二氧化硅纳米微粒的胶原支架作为本研究的对照组.通过对复合材料的物理化学性质,包括湿度、表面化学、孔隙率、溶胀率、降解行为进行了评价,并且通过复合支架培养骨髓间充质干细胞（BMSCs）,观察这种新型复合材料在生物学方面的特性.结果 二氧化硅纳米微粒呈球形,平均直径分布在150 nm～190 nm,所有样品接触角排序为：单胶原支架＜（5μg/ml）复合支架＜（10μg/ml）复合支架＜（25 μg/ml）复合支架≈（50、100 μg/ml）复合支架,FHR谱表明纳米微粒在胶原支架内成功添加;扫描电子显微镜（SEM）观察复合胶原支架虽然添加纳米微粒仍然保持相似的多孔微结构,包括孔尺寸、形状和网状结构.将复合支架的纳米微粒浓度增加,孔隙率却呈减小趋势,溶胀率也随微粒的浓度增加而降低,纳米微粒可明显抑制单胶原支架的快速降解;支架内BMSCs的活性和增殖度先升高,后随着颗粒浓度的增加而降低,25 μg/ml时细胞增殖活性最好（P＜0.05）.结论 25 μg/ml二氧化硅纳米微粒的掺入可以提高支架疏水性,降低孔隙率、膨胀率和降解速率,细胞在此种浓度下生长较好.

Objective To estimate the function of collagen and silica nanoparticles in the process of constructing tissue-engineered never scaffolds.Methods The silica nanoparticles of various concentrations （5,10,25,50 and 100 μg/ml） were synthesized in collagen solution and formed to silica incorporated porous collagen structures by freeze-drying technology.As the control,the collagen scaffold was prepared through same methods that do not contain silica nanoparticles.We examined various properties such as morphology,chemical composition,wettability,porosity,swelling ratio and degradation behavior of the composite scaffolds.The bone marrow mesenchymal stem cells （BMSCs） were cultured in this scaffold.Results The average diameter of the nanoparticles mainly distributed from 150 to 190 nm.The contact angles of all the samples increased in the order of：single collagen scaffolds/collagen/silica （5 μg/ml） composite scaffolds/collagen/silica （10 μg/ml） composite scaffolds/collagen/silica （25 μg/ml） composite scaffolds ＆amp; collagen/silica （50,100 μg/ml） composite scaffolds.The scanning election microscopy （SEM） images of the scaffold with various silica ratios.The composite collagen scaffolds still kept the similar porous microstructures,including the pore size,shape,and interconnection network,with the single collagen scaffolds,though the addition of silica nanoparticles.The DNA contents of BMSCs in scaffolds also increased firstly and then decreased with the increment of silica nanoparticles concentration,and the cells in the composite scaffolds with 25 μg/ml silica nanoparticles showed the largest DNA contents.Conclusion The incorporation of 25 μg/ml silica nanoparticles could increase the hydrophobicity,decrease porosity,swelling ratio and degradation rate of the collagen scaffolds and the BMSCs have a good status in this concentration.