Organised neural networks in culture

Abstract

The aim of my research was to recreate simple, spatially organised neural networks in culture for the study of neural network behaviour. Spinal cord neurons were chosen as the biological model, as much is already known about spinal cord tissue circuitry in-vivo. These simple networks of cells were created by chemical patterning techniques (micro-contact printing (mCP)), and topographical guidance mechanisms. mCP was used to test the hypothesis that alterations in network architecture could affect network behaviour. Changes in network structures were identified, using immunocytochemical staining and scanning electron microscopy (SEM). Of the six patterns tested it was concluded that the Jude pattern did not satisfy the criteria required for a neural network. Cells failed to comply to the extreme angles of this design and so a hexagonal pattern was introduced. Dendritic architecture, of varying designs, was incorporated into these hexagonal networks with the aim of determining if variation in dendritic arborisation could affect network activity. An analysis of the result showed that cell morphology and connectivity was visibly altered, suggesting network characteristics were affected. An attempt was made to create organised nerve cultures using micro-metric grooved patterns in poly-dimethylsiloxane (PDMS). The cellular response was determined by immunocytochemical staining and SEM imaging. Cells grown on micrometric topographical patterns did not align within the grooves as predicted. Therefore the effect of nano-metric pillared topography, created in poly-caprolactone, on nerve cell guidance was investigated. In comparison to the flat material, this nanotopography reduced cell adhesion, although it was not completely non-adhesive. After 1 week cells were visibly aligning to the topography, at the micro-and nanometric level, and appeared to be growing longer processes compared to the cells grown on flat structures. This result suggests nanopillared topography has a promising future in nerve guidance studies