Bellamkonda R, Ranieri J P, Bouche N, Aebischer P
Division of Surgical Research, Centre Hospitalier Universitaire Vaudois, Lausanne University Medical School, Switzerland.
J Biomed Mater Res. 1995 May;29(5):663-71. doi: 10.1002/jbm.820290514.
The ability to organize cells in three dimensions (3D) is an important component of tissue engineering. This study sought to develop an extracellular matrix (ECM) equivalent with a physicochemical structure capable of supporting neurite extension from primary neural cells in 3D. Rat embryonic day 14 striatal cells and chick embryonic day 9 dorsal root ganglia extended neurites in 3D in agarose hydrogels in a gel concentration-dependent manner. Primary neural cells did not extend neurites above a threshold agarose gel concentration of 1.25% wt/vol. Gel characterization by hydraulic permeability studies revealed that the average pore radius of a 1.25% agarose gel was 150 mm. Hydraulic permeability studies for calculating average gel pore radius and gel morphology studies by environmental and scanning electron micrography showed that the average agarose gel por size decreased exponentially as the gel concentration increased. It is hypothesized that the average gel porosity plays an important role in determining the ability of agarose gels to support neurite extension. Lamination of alternating nonpermissive, permissive, and nonpermissive gel layers facilitated the creation of 3D neural tracts in vitro. This ability of agarose hydrogels to organize, support, and direct neurite extension from neural cells may be useful for applications such as 3D neural cell culture and nerve regeneration. Agarose hydrogel substrates also offer the possibility of manipulating cells in 3D, and may be used as 3D templates for tissue engineering efforts in vitro and in vivo.
在三维空间（3D）中组织细胞的能力是组织工程的一个重要组成部分。本研究旨在开发一种具有物理化学结构的细胞外基质（ECM）等效物，该结构能够支持原代神经细胞在3D环境中的神经突延伸。大鼠胚胎第14天的纹状体细胞和鸡胚胎第9天的背根神经节在琼脂糖水凝胶中以凝胶浓度依赖性方式在3D环境中延伸神经突。当琼脂糖凝胶浓度超过1.25%（重量/体积）的阈值时，原代神经细胞不再延伸神经突。通过水力渗透率研究对凝胶进行表征发现，1.25%琼脂糖凝胶的平均孔径为150μm。通过环境和扫描电子显微镜进行的用于计算平均凝胶孔径的水力渗透率研究以及凝胶形态学研究表明，随着凝胶浓度的增加，琼脂糖凝胶的平均孔径呈指数下降。据推测，平均凝胶孔隙率在决定琼脂糖凝胶支持神经突延伸的能力方面起着重要作用。交替排列非允许、允许和非允许凝胶层有助于在体外创建3D神经束。琼脂糖水凝胶组织、支持和引导神经细胞神经突延伸的这种能力可能对3D神经细胞培养和神经再生等应用有用。琼脂糖水凝胶基质还提供了在3D环境中操纵细胞的可能性，并且可作为体外和体内组织工程研究的3D模板。
