Micropatterning neuronal networks on nanofiber platforms

摘要

Neuronal networks are groups of interconnected cells in the Central Nervous System (CNS) or the Peripheral Nervous System (PNS) that function in many different ways. They can provide function in the sympathetic nervous system, in a sensory circuit in the spinal column, or can be a high level processing unit in a cortex. If neuronal networks lose their ability to perform their function, this can ultimately lead to a neurological disorder in the body. Therefore it is important to conduct research on neuronal networks to better understand the underlying mechanisms of neurological disorders. Even though there has been a considerable amount of useful research conducted on neuronal networks, the connections in those neuronal networks are random. There are massive amounts of connections in a mammalian brain, so the ability to guide the connections for studying neural networks is of vital importance. In order to better understand how the brain stores and processes information, the complexity associated with neuronal networks has to be reduced. Cell patterning is a potential solution to this problem and allows simplified and organized neuronal networks. In this thesis cell patterning using microfabrication techniques is discussed and a microfabricated device that was patterned on biocompatible extracellular matrix (ECM)-like polymer electrospun nanofibers is introduced. Our device was able to pattern, organize, and simplify neuronal networks. We hypothesized that physical confinement of neural cells and limited routes of neurite extension would contribute to reduced proliferation, increased differentiation, and therefore enable the formation of more robust neural networks. The effect of cell confinement as well as the use of vacuum seeding on neural network formation was compared to cell growth on collagen-coated tissue culture polystyrene and nanofiber mats with no confining microstructures. To test the effects of the underlying nanofibers on the neural network formation, we fabricated our device on both random and aligned nanofibers. We evaluated performance of our device from a neural tissue engineering perspective. Finally, the results of various biological responses, i.e. adhesion, viability, and differentiation, of cells on our devices on random and aligned nanofibers are discussed.