| Description |
The goal of the research outline in this work was to characterize the effects of surface chemistry, intermediary proteins, and topography on the behavior of cell derived from the nervous system. These studies were initiated in order to provide input specifications for the design of improved bioartificial substrates for use in promoting nerve regeneration. The development of synthetic material based devices for restoring damaged neuronal tracts in an area of expanding scientific effort. A critical factor in the development of such devices is an understanding of the cell-material interactions and methods to manipulate these interactions in the target host tissue. To this end, two important cell types of the nervous system were examined: astrocytes, which represent an important wound healing type in the CNS, and neurons. In the first study, the attachment and growth of primary astrocytes (Chapter 4) and neurons (Appendix A) were characterized on polymeric materials of varying surface chemistries. Although differences in attachment and growth were evident initially, over time in culture astrocytes were capable to forming confluent monolayers on all the materials. On the other hand, little correlation was observed between neuronal behavior and material wettability. Neurite outgrowth, however, appeared to be highly sensitive to the presence of serum. In the second, study, a method for immobilizing proteins to surfaces in serum-resistant manner was examined for its effects on neuronal attachment and outgrowth. Attachment and outgrowth could be controlled in a dose-dependent and serum-resistant manner only on immobilized but no absorbed FN. The third study investigated the behaviors of PNS and CNS neurons on differing surface topographies. The effect of groove depth on the alignment and orientation of neurite outgrowth was measured. Neuronal alignment along the longitudinal axis of the grooves was influenced by groove depth and neuron type. Neurons also aligned even when an underlying support layer of astrocytes was plated onto the grooved substrate, indicating that physical cues could be transduced through multiple cell layers. Together these studies demonstrate the importance and potential utility of controlling not only the intermediary protein layer on the material surface, but the potential application of surface topography, possible even through multiple cell layers, to control and direct neuronal behaviors. In the future, such strategies may be implemented in the design of novel biomaterial-based devices for applications in the nervous system. |
