Investigations of Complex Guidance Cues for Nerve Regeneration Using Novel In Vitro Platforms Kofron, Celinda M. creator 2009 xvi, 223 p. born digital Thesis (Ph.D.) -- Brown University (2009) Hoffman-Kim, Diane director Morgan, Jeffrey reader Palmore, Tayhas reader Webster, Thomas reader Thompson, Deanna reader Brown University. Biomedical Engineering sponsor theses Neurons have highly developed pathfinding abilities, but in any part of the nervous system, during development or after the challenge of injury, cues provided by the local environment are required to trigger growth, direct paths, and guide connection or reconnection with appropriate targets. Study of these cues with in vitro platforms that are closer to in vivo environments in architecture and complexity provide insights into neuronal integration of cues to inform strategies for nerve regeneration. Oriented tissue structures guide neurons in vitro and in vivo. Biomimetic replica materials presenting aligned glial or non-glial cellular topographies, which isolate physical cues from biochemical cues, were all shown to guide neuronal growth despite distinct topographies and anisotropies presented by different cells. Application of statistical design and analysis methods improved efficiency and utility in determining optimal conditions for generating cellular monolayers for replication. Neuronal growth on materials presenting sharper, higher edges was more directed than growth on biomimetic materials suggesting that the topography of anisotropic tissues are sufficient for guidance, but may not be optimal for precise control of directed neuronal growth. These biomimetic replica materials were also investigated in combination with permissive and inhibitory biochemical cues to identify collaborative and hierarchical effects of directive cues. Neurons exhibited directional preference for biochemical cues over cellular topographies in the limited range of protein concentrations and patterns tested. Comparison of the relative strength of cues when presented individually did not effectively predict the hierarchy or accord of these cues when presented together. Neuronal preference for biochemical tracks was also examined in a three dimensional (3D) model. In two dimensions, neurons align on permissive protein tracks and between inhibitory tracks. Neurons also aligned to permissive tracks at the surface of a 3D platform, but extended away from the surface in 3D when an inhibitory molecule was presented. These findings increase the understanding of neuronal response to structurally complex environments and provide insights into the net response of neurons to multiple cooperating or competing cues. Schwann cell design of experiments response surface methodology axon guidance NeuronsAstrocytesEndothelial cellsExperimental designPhotolithography RPB 20091218 engEnglish10.7301/Z0JQ0Z9WIn CopyrightCollection is open for research.dissertations