Manjubala I, Ponomarev Igor, Wilke Ingo, Jandt Klaus D
Department of Biomaterials, Max-Planck Institute for Colloids and Interfaces, 14424 Potsdam, Germany.
J Biomed Mater Res B Appl Biomater. 2008 Jan;84(1):7-16. doi: 10.1002/jbm.b.30838.
Porous scaffold materials that can provide a framework for the cells to adhere, proliferate, and create extracellular matrix are considered to be suitable materials for bone regeneration. Interconnected porous chitosan scaffolds were prepared by freeze-drying method, and were mineralized by calcium and phosphate solution by double-diffusion method to form nanoapatite in chitosan matrix. The mineralized chitosan scaffold contains hydroxyapatite nanocrystals on the surface and also within the pore channels of the scaffold. To assess the effect of apatite and porosity of the scaffolds on cells, human osteoblast (SaOS-2) cells were cultured on unmineralized and mineralized chitosan scaffolds. The cell growth on the mineralized scaffolds and on the pure chitosan scaffold shows a similar growth trend. The total protein content and alkaline phosphatase enzyme activity of the cells grown on scaffolds were quantified, and were found to increase over time in mineralized scaffold after 1 and 3 weeks of culture. The electron microscopy of the cell-seeded scaffolds showed that most of the outer macropores became sealed off by a continuous layer of cells. The cells spanned around the pore wall and formed extra cellular matrix, consisting mainly of collagen in mineralized scaffolds. The hydroxyproline content also confirmed the formation of the collagen matrix by cells in mineralized scaffolds. This study demonstrated that the presence of apatite nanocrystals in chitosan scaffolds does not significantly influence the growth of cells, but does induce the formation of extracellular matrix and therefore has the potential to serve for bone tissue engineering.
能够为细胞提供附着、增殖和产生细胞外基质框架的多孔支架材料被认为是适合骨再生的材料。通过冷冻干燥法制备了相互连通的多孔壳聚糖支架，并通过双扩散法用钙和磷酸盐溶液对其进行矿化，以在壳聚糖基质中形成纳米磷灰石。矿化的壳聚糖支架在表面以及支架的孔道内都含有羟基磷灰石纳米晶体。为了评估支架的磷灰石和孔隙率对细胞的影响，将人成骨细胞（SaOS-2）培养在未矿化和矿化的壳聚糖支架上。在矿化支架和纯壳聚糖支架上的细胞生长显示出相似的生长趋势。对在支架上生长的细胞的总蛋白含量和碱性磷酸酶活性进行了定量，发现在培养1周和3周后，矿化支架中的细胞总蛋白含量和碱性磷酸酶活性随时间增加。接种细胞的支架的电子显微镜检查表明，大多数外部大孔被一层连续的细胞封闭。细胞跨越孔壁并形成细胞外基质，在矿化支架中主要由胶原蛋白组成。羟脯氨酸含量也证实了矿化支架中的细胞形成了胶原蛋白基质。这项研究表明，壳聚糖支架中磷灰石纳米晶体的存在不会显著影响细胞的生长，但会诱导细胞外基质的形成，因此具有用于骨组织工程的潜力。
