Development of Strategies to Enable biomimetic Stimulation of Retinal Ganglion Cells (RGC)

The current work is motivated by the need to treat incurable vision loss due to photoreceptor degenerative diseases. Photoreceptors are specialized neurons in the retina that convert light into electrochemical signals. These signals are processed by another class of neurons called the retinal ganglion cells which remain unaffected by the disease progression. We are motivated by the need for an implantable device to chemically stimulate retinal ganglion cells to treat these incurable photoreceptor degenerative diseases. This form of treatment is based on the replication of the functionality of the photoreceptors in the natural vision process and is therefore considered biomimetic. The materials used to fabricate these devices must either be known biocompatible materials or should be tested for their biocompatibility. The conceptualized implantable device is an opto-fluidic artificial retinal chemical synapse (ARCS) chip that releases precise qualities of a neurotransmitter called glutamate to stimulate the retinal ganglion cells and restore vision. The aim of this thesis is the identification and development of different strategies to enable the ARCS chip. The organization and the fulfilment of goals of this thesis is guided through the research contributions to three specific aims listed below: 1. Improving the yield of 3-D SU-8 fabrication methods. 2. Development of non-destructive metrological techniques to characterize surface and subsurface microfeatures of polymer-based microstructures. 3. Development of a multipore independently addressable biocompatible electroosmotic micropump