Biomimetic MEMS Technology for a Novel Retinal Prosthesis

1. Biomimetic MEMS Technology for a Novel Retinal Prosthesis PI: LaxmanSaggere, Mechanical and Industrial EngineeringCollaborator: David Schneeweis, BioEngineering Prime Grant Support: National Science Foundation • Motivation: Photoreceptor degeneration in diseases such as ARMD and RP is the leading cause of blindness in the world. No cures or therapies are available for these diseases, but a retinal-based prosthesis offers a promising treatment option. Most current retinal prostheses rely on the concept of electrical stimulation of neurons, which is conceptually simple, but faced with many challenges • Objective: To develop a biomimetic technology enabling a fundamentally different and technically superior approach to a retinal prosthesis. This approach, in principle, mimics a natural photoreceptor’s function of transducing visual stimuli into chemical signals that stimulate the surviving retinal neurons. • Approach: A microdispenser unit integrated with a miniaturized solar cell and a thin-film piezo actuator on one side and several micron-scale ports on the other side contains liquid chemical (neurotransmitter). An array of such microdispenser units constitutes the core of a prosthesis. • Principle of Operation: Light falling on the retina irradiates the solar cell, which generates voltage across the piezo actuator. The actuator pressurizes the liquid and dispenses it through the micro ports. The liquid diffuses through micro-capillaries in a soft encapsulation and stimulates retinal cells. • Technologies: MEMS, microfluidics, thin-film piezoelectric actuators, solid-sate solar cells, chemical cellular signaling. • Challenges: i)Low intensity light at the retina; ii) Integration of array components and microfluidics; iii) Chemical dispensing rate, mechanism, long-term operation; iv) Biocompatible packaging. • Key Achievements:i) Completed preliminary system design and established the concept feasibility; ii) Established a technique to chemically stimulate neuronal cells and record the cellular response; iii) Fabricated and characterized the light powered actuator; iv) Established techniques to quantify nanoliter flow • Future Goals:i) To fabricate and test an in-vitro proof of the concept device; ii) To lead the technology developed towards clinical relevancy through interdisciplinary collaborations with neuroscientists and retina specialists.