Abstract
Abstract: :
Purpose: We have developed a microfluidic retinal prosthesis, using wide bandgap semiconductor thin film waveguides, to facilitate spatial and quantitative photactivation of caged neurotransmitter to microfluidic channels. Methods: Novel waveguide materials and micromachining technology is necessary to fabricate 360 nanometer capable waveguides for the microfluidic device. Single crystal wide bandgap semiconductor thin films are grown on sapphire with high refractive index buffer layer by plasma source molecular beam epitaxy (PSMBE). 248 nanometer KrF Excimer laser micromachining technology is employed to micro-fabricate wave-guiding channels and microfluidic structures. Results: A waveguide which allows for spatial and temporal drug delivery within the retina was fabricated. Wave-guiding channels were precisely fabricated to form a cavity to maximize the intensity of ultraviolet light. Wave-guiding properties were efficiently characterized as a function of thickness, geometry and crystalline quality. Conclusion: There is a need for a waveguide structure that may be used in physiological drug delivery systems. A device that may deliver ultraviolet light in precise amounts and to selective areas of a microfluidic implant without direct ultraviolet exposure to the biological cells is much needed in retinal and cortical implants. Results of a prototype microfluidic waveguide system will be presented.
Keywords: 554 retina • 490 neurotransmitters/neurotransmitter systems • 556 retina: neurochemistry