This project addresses, proposes, develops, and prototypes a core component of an NIH-motivated program to develop a silicon-based closed-loop drug delivery system targeted for insulin therapy of diabetics. The component, a silicon microvalve, fulfills a need for a low-power, low-cost and miniaturized (<0.25 cm3) insulin metering device with the ability to control precise and fractional (nanoliter) volume of fluids. Innovative new designs, efficient usage of materials, and emerging methods for repeatable, manufacturable, and wafer-scale fabrication and assembly of piezoelectric actuators on silicon wafers, allow for 10-100 times larger static displacements and forces than previously attainable, at the same or lower power levels, and at lower cost. Phase I will address design issues, challenges in assembly, materials and fluids compatibility, and prototyping of engineering-spec-driven microvalves for end-users. These specifications will be detailed in acceptable leak rates, peak and average power-levels, operating pressure ranges, management of occlusions, and long-term cyclic loading conditions. The technical feasibility will be assessed using these metrics. Validation for Phase II will come from end-user feedback, and will lead to design refinements, process improvements, and cost- reduction. The adaptability of the proposed component, its low-power capabilities for portability, and its large dynamic range has applications in valving, metering, and pressure regulation for in-vitro and in-vivo drug delivery, intraocular pressure (IOP) relief for glaucoma, pressure management for hydrocephalus, and gas flow control in breathalyzers. The design philosophy and the manufacturing approach taken, while generating many progenitor component products, lends itself broadly to a silicon platform for integration of sensors and electronics, and in this specific case, to a microvalve technology that fits into a vision for a closed-loop insulin delivery system.
Diabetes affects 24 million people in the United States, an additional 57 million are pre-diabetic, and the numbers and percentages are growing. This project develops a core component of an """"""""artificial pancreas"""""""" - a silicon microvalve. An artificial pancreas substitutes for the real organ that in Type 1 patients has become dysfunctional. The microvalve will fulfill a need for a low-power and inexpensive insulin delivery device utilizing new designs and materials to meet performance specifications previously unattainable. The microvalve is a key step towards an integrated system that will be less bulky, less expensive, and more intelligent than conventional solutions, and is developed on a manufacturing platform for efficient and ready integration of sensors and electronics.