Baumgartner Walter, Welti Manfred, Hild Nora, Hess Samuel C, Stark Wendelin J, Bürgisser Gabriella Meier, Giovanoli Pietro, Buschmann Johanna
Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland.
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland.
J Mech Behav Biomed Mater. 2015 Jul;47:124-134. doi: 10.1016/j.jmbbm.2015.03.022. Epub 2015 Apr 2.
Perfusion bioreactors are used to solve problems in critical size bone tissue engineering. Biominerizable and biocompatible nanocomposites are suitable scaffold materials for this purpose because they offer mineral components in organic carriers. Human adipose derived stem cells (ASCs) can potentially be used to increase bone healing.
Electrospun nanocomposite disks of poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/a-CaP) were seeded with ASCs and eight disks were stacked in a bioreactor running with normal culture. Under perfusion and uniaxial cyclic compression, load-displacement curves as a function of time were assessed. Stiffness and energy dissipation were recorded. Moreover, stem cell densities in the layers of the piled scaffold were determined as well as their morphologies and differentiation status.
While the stiffness of the cell free constructs increased over time based on the transformation of the a-CaP nanoparticles into flake-like apatite, ASC-seeded constructs showed a constant stiffness. Stem cell density gradients had a linear increase from the bottom to the top of the pile (r(2)>0.95). Stem cells were getting more roundish at higher flow rates. Some osteogenesis was found upon osteopontin immunostaining, while no endothelial cell differentiation and no chondrogenesis was triggered.
The fabrication of a critical size bone graft is presented based on a biominerizable bone-biomimetic nanocomposite with preserved stiffness when seeded with ASCs. The cell densities of ASCs inside the piled construct varied with a linear gradient. Beginning osteogenesis was triggered by the dynamic culture conditions including perfusion and compression.
灌注生物反应器用于解决临界尺寸骨组织工程中的问题。可生物矿化且具有生物相容性的纳米复合材料是适用于此目的的支架材料，因为它们在有机载体中提供矿物质成分。人脂肪来源干细胞（ASC）有可能用于促进骨愈合。
将聚乳酸 - 乙醇酸共聚物和无定形磷酸钙纳米颗粒（PLGA/a-CaP）的电纺纳米复合盘接种ASC，并将八个盘堆叠在正常培养运行的生物反应器中。在灌注和单轴循环压缩下，评估作为时间函数的载荷 - 位移曲线。记录刚度和能量耗散。此外，还测定了堆积支架各层中的干细胞密度及其形态和分化状态。
虽然基于a-CaP纳米颗粒向片状磷灰石的转变，无细胞构建体的刚度随时间增加，但接种ASC的构建体显示出恒定的刚度。干细胞密度梯度从堆的底部到顶部呈线性增加（r(2)>0.95）。在较高流速下，干细胞变得更圆。骨桥蛋白免疫染色发现有一些成骨现象，而未引发内皮细胞分化和软骨形成。
基于一种可生物矿化的骨仿生纳米复合材料，展示了临界尺寸骨移植体的制造方法，接种ASC时其刚度得以保留。堆积构建体内ASC的细胞密度呈线性梯度变化。包括灌注和压缩在内的动态培养条件引发了早期成骨。
