Surface organic- and nano-chemistry approach to study on neuron-material interfaces

Abstract

This dissertation deals with the chemical/topographical modifications of neuron/material interfaces (NMI) and their effects on neuronal behaviors. Hippocampal neurons were cultured on various surfaces for the generation in vitro neural networks, and the morphological and functional properties of them were analyzed by light microscopy and microelectrode arrays (MEAs), respectively. Chemically functionalized NMIs included surface-initiated polymer films and self-assembled bio-inspired polymer films, and anodized aluminum oxide (AAO) nanostructures and assembled silica nanobead (SB) monolayers were fabricated for providing nanotopo-graphical environments to neurons. Observed neuronal responses to these NMIs included the formation of pat-terned neuronal networks, favored attachment and functional connections, and accelerated neurite devel-opment. The patterned neural network was generated by surface-initiated, atom transfer radical polymerization of oligo(ethylene glycol) methacrylate (OEGMA), leading to the formation of pOEGMA films. The pOEGMA films exhibited highly cell-repellent characteristics due to the densely-packed poly(ethylene glycol) structures, and therefore they were expected to be an appropriate platform for patterned neural network with long-term stability. Surface-initiated polymerization of the pOEGMA films, activation of the terminal hydroxyl groups, microcontact printing of cell-adhesive molecules, and passivation of the off-pattern region were sequentially implemented, and the robust neuronal patterns were obtained. The functional interconnections between the neurons in the patterned networks were confirmed by patch clamping. As a biofunctionalization of electrode-based NMIs, polydopamine (PolyDA) films were introduced. PolyDA films have been reported to be a substrate-independent coating method, and capable of further modifications with many biomolecules, which were advan-tageous for multimaterial-based and multifunctional neural electrode d...