School of Chemical Engineering, University of Birmingham, Birmingham B152TT, UK.
Acta Biomater. 2010 Sep;6(9):3649-56. doi: 10.1016/j.actbio.2010.03.026. Epub 2010 Mar 20.
Calcium-alginate hydrogel has been widely studied as a material for cell encapsulation for tissue engineering. At present, the effect that cells have on the degradation of alginate hydrogel is largely unknown. We have shown that fibroblasts encapsulated at a density of 7.5 x 10(5) cells ml(-1) in both 2% and 5% w/v alginate remain viable for at least 60 days. Rheological analysis was used to study how the mechanical properties exhibited by alginate hydrogel changed during 28 days in vitro culture. Alginate degradation was shown to occur throughout the study but was greatest within the first 7 days of culture for all samples, which correlated with a sharp release of calcium ions from the construct. Fibroblasts were shown to increase the rate of degradation during the first 7 days when compared with acellular samples in both 2% and 5% w/v gels, but after 28 days both acellular and cell-encapsulating samples retained disc-shaped morphologies and gel-like spectra. The results demonstrate that although at an early stage cells influence the mechanical properties of encapsulating alginate, over a longer period of culture, the hydrogels retain sufficient mechanical integrity to exhibit gel-like properties. This allows sustained immobilization of the cells at the desired location in vivo where they can produce extracellular matrix and growth factors to expedite the healing process.
海藻酸钠水凝胶作为组织工程细胞包封的材料已得到广泛研究。目前，细胞对海藻酸钠水凝胶降解的影响在很大程度上尚不清楚。我们已经表明，在 2%和 5%w/v 海藻酸钠中以 7.5 x 10(5)个细胞/ml(-1)的密度包封的成纤维细胞在至少 60 天内保持存活。流变分析用于研究海藻酸钠水凝胶在体外培养 28 天过程中表现出的机械性能如何变化。研究表明，海藻酸盐降解在整个研究过程中均发生，但在所有样品的培养前 7 天内最为严重，这与从构建体中迅速释放钙离子相关。与无细胞样品相比，细胞在 2%和 5%w/v 凝胶中的第 1 天降解速度更快，但在 28 天后，无细胞和细胞包封的样品均保留圆盘状形态和凝胶状光谱。结果表明，尽管在早期阶段细胞会影响包封海藻酸钠的机械性能，但在较长的培养过程中，水凝胶仍保持足够的机械完整性以表现出凝胶状特性。这允许细胞在体内所需位置进行持续固定，在那里它们可以产生细胞外基质和生长因子，以加速愈合过程。
