Selective axonal growth of embryonic hippocampal neurons according to topographic features of various sizes and shapes

Original Research

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Authors: David Y Fozdar, Jae Y Lee, Christine E Schmidt, et al

Published Date December 2010 Volume 2011:6 Pages 45 - 57

DOI: http://dx.doi.org/10.2147/IJN.S12376

David Y Fozdar^1*, Jae Y Lee^2*, Christine E Schmidt^2–6, Shaochen Chen^1,3–5,7,

¹Departments of Mechanical Engineering, ²Chemical Engineering, ³Biomedical Engineering; ⁴Center for Nano Molecular Science and Technology; ⁵Texas Materials Institute; ⁶Institute of Neuroscience; ⁷Microelectronics Research Center, The University of Texas at Austin, Austin, TX, USA
*Contributed equally to this work

Purpose: Understanding how surface features influence the establishment and outgrowth of the axon of developing neurons at the single cell level may aid in designing implantable scaffolds for the regeneration of damaged nerves. Past studies have shown that micropatterned ridge-groove structures not only instigate axon polarization, alignment, and extension, but are also preferred over smooth surfaces and even neurotrophic ligands.
Methods: Here, we performed axonal-outgrowth competition assays using a proprietary four-quadrant topography grid to determine the capacity of various micropatterned topographies to act as stimuli sequestering axon extension. Each topography in the grid consisted of an array of microscale (approximately 2 µm) or submicroscale (approximately 300 nm) holes or lines with variable dimensions. Individual rat embryonic hippocampal cells were positioned either between two juxtaposing topographies or at the borders of individual topographies juxtaposing unpatterned smooth surface, cultured for 24 hours, and analyzed with respect to axonal selection using conventional imaging techniques.
Results: Topography was found to influence axon formation and extension relative to smooth surface, and the distance of neurons relative to topography was found to impact whether the topography could serve as an effective cue. Neurons were also found to prefer submicroscale over microscale features and holes over lines for a given feature size.
Conclusion: The results suggest that implementing physical cues of various shapes and sizes on nerve guidance conduits and other advanced biomaterial scaffolds could help stimulate axon regeneration.

Keywords: axon guidance, micropatterning, polarization, surface topography, tissue engineering

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