Nava Michele M, Draghi Lorenza, Giordano Carmen, Pietrabissa Riccardo
Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan - Italy.
Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan - Italy.
J Appl Biomater Funct Mater. 2016 Jul 26;14(3):e223-9. doi: 10.5301/jabfm.5000302.
The effect of scaffold pore size and interconnectivity is undoubtedly a crucial factor for most tissue engineering applications. The aim of this study was to examine the effect of pore size and porosity on cartilage construct development in different scaffolds seeded with articular chondrocytes.
We fabricated poly-L-lactide-co-trimethylene carbonate scaffolds with different pore sizes, using a solvent-casting/particulate-leaching technique. We seeded primary bovine articular chondrocytes on these scaffolds, cultured the constructs for 2 weeks and examined cell proliferation, viability and cell-specific production of cartilaginous extracellular matrix proteins, including GAG and collagen.
Cell density significantly increased up to 50% with scaffold pore size and porosity, likely facilitated by cell spreading on the internal surface of bigger pores, and by increased mass transport of gases and nutrients to cells, and catabolite removal from cells, allowed by lower diffusion barriers in scaffolds with a higher porosity. However, both the cell metabolic activity and the synthesis of cartilaginous matrix proteins significantly decreased by up to 40% with pore size. We propose that the association of smaller pore diameters, causing 3-dimensional cell aggregation, to a lower oxygenation caused by a lower porosity, could have been the condition that increased the cell-specific synthesis of cartilaginous matrix proteins in the scaffold with the smallest pores and the lowest porosity among those tested.
In the initial steps of in vitro cartilage engineering, the combination of small scaffold pores and low porosity is an effective strategy with regard to the promotion of chondrogenesis.
支架孔径和连通性的影响无疑是大多数组织工程应用中的关键因素。本研究的目的是研究孔径和孔隙率对接种关节软骨细胞的不同支架中软骨构建体发育的影响。
我们使用溶剂浇铸/颗粒沥滤技术制备了具有不同孔径的聚-L-丙交酯-共-三亚甲基碳酸酯支架。我们将原代牛关节软骨细胞接种在这些支架上，培养构建体2周，并检测细胞增殖、活力以及软骨细胞外基质蛋白（包括糖胺聚糖和胶原蛋白）的细胞特异性产生。
随着支架孔径和孔隙率的增加，细胞密度显著增加高达50%，这可能是由于细胞在较大孔隙的内表面铺展，以及孔隙率较高的支架中扩散屏障较低，使得气体和营养物质向细胞的质量传输增加，细胞分解代谢产物从细胞中排出增加所致。然而，细胞代谢活性和软骨基质蛋白的合成均随着孔径的增加显著降低高达40%。我们认为，较小的孔径导致三维细胞聚集，以及较低的孔隙率导致较低的氧合作用，可能是在测试中具有最小孔径和最低孔隙率的支架中增加软骨基质蛋白细胞特异性合成的条件。
在体外软骨工程的初始步骤中，小支架孔径和低孔隙率的组合是促进软骨形成的有效策略。
