Dillon G P, Yu X, Sridharan A, Ranieri J P, Bellamkonda R V
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106-7207, USA.
J Biomater Sci Polym Ed. 1998;9(10):1049-69. doi: 10.1163/156856298x00325.
Understanding neural cell differentiation and neurite extension in three-dimensional scaffolds is critical for neural tissue engineering. This study explores the structure-function relationship between a 3D hydrogel scaffold and neural cell process extension and examines the role of ambient charge on neurite extension in 3D scaffolds. A range of agarose hydrogel concentrations was used to generate varied gel physical structures and the corresponding neurite extension was examined. Agarose gel concentration and the corresponding pore radius are important physical properties that influence neural cell function. The average pore radii of the gels were determined while the gel was in the hydrated state and in two different dehydrated states. As the gel concentration was increased, the average pore radius decreased exponentially. Similarly, the length of neurites extended by E9 chick DRGs cultured in agarose gels depends on gel concentration. The polycationic polysaccharide chitosan and the polyanionic polysaccharide alginate were used to incorporate charge into the 3D hydrogel scaffold, and neural cell response to charge was studied. Chitosan and alginate were covalently bound to the agarose hydrogel backbone using the bi-functional coupling agent 1,1'-carbonyldiimidazole. DRGs cultured in chitosan-coupled agarose gel exhibited a significant increase in neurite length compared to the unmodified agarose control. Conversely, the alginate-coupled agarose gels significantly inhibited neurite extension. This study demonstrates a strong, correlation between the ability of sensory ganglia to extend neurites in 3D gels and the hydrogel pore radius. In addition, our results demonstrate that charged biopolymers influence neurite extension in a polarity dependent manner.
了解神经细胞在三维支架中的分化和神经突延伸对于神经组织工程至关重要。本研究探讨了三维水凝胶支架与神经细胞突起延伸之间的结构-功能关系，并研究了环境电荷对三维支架中神经突延伸的作用。使用一系列琼脂糖水凝胶浓度来生成不同的凝胶物理结构，并检测相应的神经突延伸情况。琼脂糖凝胶浓度和相应的孔径是影响神经细胞功能的重要物理特性。在水合状态以及两种不同的脱水状态下测定凝胶的平均孔径。随着凝胶浓度的增加，平均孔径呈指数下降。同样，在琼脂糖凝胶中培养的E9期鸡背根神经节（DRG）延伸的神经突长度取决于凝胶浓度。使用聚阳离子多糖壳聚糖和聚阴离子多糖海藻酸盐将电荷引入三维水凝胶支架，并研究神经细胞对电荷的反应。壳聚糖和海藻酸盐使用双功能偶联剂1,1'-羰基二咪唑与琼脂糖水凝胶主链共价结合。与未修饰的琼脂糖对照相比，在壳聚糖偶联的琼脂糖凝胶中培养的DRG神经突长度显著增加。相反，海藻酸盐偶联的琼脂糖凝胶显著抑制神经突延伸。本研究表明感觉神经节在三维凝胶中延伸神经突的能力与水凝胶孔径之间存在密切相关性。此外，我们的结果表明带电生物聚合物以极性依赖的方式影响神经突延伸。
