Nerves must navigate through complex environmental cues during development and after injury to connect and reconnect with their proper targets to generate and regenerate function of the nervous system. To develop strategies for nerve repair and to understand the basic biology of nerve guidance in response to the complex cues of their environment, neurite outgrowth must be quantified in response to systematic presentations of such cues. In this thesis, neurite outgrowth and alignment strength was determined in response to molecular and topographical guidance cues as permissive extracellular matrix molecule laminin (LN) and biomimetic or cell-based microfabricated topographical features. These studies revealed several characteristics of nerve growth and decision making. Neurites responded directly to biomimetic topography on two-dimensional polymeric films and within nerve guidance conduits. Neurite outgrowth on micropatterned LN stripes depended on the micropattern characteristics, and outgrowth and alignment was complex on multi-cue platforms exhibiting strategic and simultaneous presentation of combinations of molecular and topographical cues. Neurite outgrowth was enhanced on platforms where cues were combined in parallel, while neurites preferentially aligned to one cue when cues were orthogonally opposed. Asymmetric cell-based topographical features were fabricated and Schwann cell alignment and neurite outgrowth response was assessed. Schwann cells and neurons interacted with the asymmetric features directly, exhibiting alignment and outgrowth response that depended on the feature shape and dimensions. Neuronal adhesion and neurite outgrowth were assessed in the presence of a pharmacological inhibitor of ion channels implicated in mechanosensation of environmental topographical cues to determine whether such mechanistic pathways are involved in neurite guidance on these topographical features. Neuronal adhesion and alignment were impacted as inhibitor concentration increased. This type of study has not been performed on whole cell cultures, and as such, provides insights toward a mechanistic approach to understanding nerves growth decisions on cell-based biomaterials. This research improves our understanding of basic biological questions surrounding how nerves make navigational decisions, and informs strategies of biomaterial design for therapeutic approaches toward nerve repair.
Richardson, Julie Ann,
"Neurite outgrowth in response to topographical and molecular cues"
(2012).
Biomedical Engineering Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0VQ310M
