Alvarez-Barreto Jose F, Linehan Shawna M, Shambaugh Robert L, Sikavitsas Vassilios I
School of Chemical, Biological and Materials Engineering, University of Oklahoma, Bioengineering Center, 100 E. Boyd, Rm T-335, Norman, OK 73019, USA.
Ann Biomed Eng. 2007 Mar;35(3):429-42. doi: 10.1007/s10439-006-9244-z. Epub 2007 Jan 10.
Engineered bone grafts have been generated in static and dynamic systems by seeding and culturing osteoblastic cells on 3-D scaffolds. Seeding determines initial cellularity and cell spatial distribution throughout the scaffold, and affects cell-matrix interactions. Static seeding often yields low seeding efficiencies and poor cell distributions; thus creating a need for techniques that can improve these parameters. We have evaluated the effect of oscillating flow perfusion on seeding efficiency and spatial distribution of MC3T3-E1 pre-osteoblastic cells in fibrous polystyrene matrices (20, 35 and 50-microm fibers) and foams prepared by salt leaching, using as controls statically seeded scaffolds. An additional control was investigated where static seeding was followed by unidirectional perfusion. Oscillating perfusion resulted in the most efficient technique by yielding higher seeding efficiencies, more homogeneous distribution and stronger cell-matrix interactions. Cell surface density increased with inoculation cell number and then reached a maximum, but significant detachment occurred at greater flow rates. Oxygen plasma treatment of the fibers greatly improved seeding efficiency. Having similar porosity and dimensions, fibrous matrices yielded higher cell surface densities than foams. Fluorescence microscopy and histological analyses in polystyrene and PLLA scaffolds demonstrated that perfusion seeding produced more homogeneous cell distribution, with fibrous matrices presenting greater uniformity than the foams.
通过在三维支架上接种和培养成骨细胞，已在静态和动态系统中生成了工程化骨移植物。接种决定了整个支架的初始细胞密度和细胞空间分布，并影响细胞与基质的相互作用。静态接种往往导致接种效率低和细胞分布不佳；因此需要能够改善这些参数的技术。我们评估了振荡流灌注对MC3T3-E1前成骨细胞在纤维聚苯乙烯基质（20、35和50微米纤维）以及通过盐析制备的泡沫中的接种效率和空间分布的影响，并将静态接种的支架作为对照。还研究了另一种对照，即静态接种后进行单向灌注。振荡灌注通过产生更高的接种效率、更均匀的分布和更强的细胞与基质相互作用，成为最有效的技术。细胞表面密度随接种细胞数量增加，然后达到最大值，但在更高流速下会发生明显的细胞脱离。纤维的氧等离子体处理极大地提高了接种效率。具有相似孔隙率和尺寸的纤维基质比泡沫产生更高的细胞表面密度。聚苯乙烯和聚乳酸支架中的荧光显微镜和组织学分析表明，灌注接种产生了更均匀的细胞分布，纤维基质比泡沫呈现出更大的均匀性。
