Development of a Microfluidic Insulin Pump
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Michael Clements |
Introduction to Diabetes & Insulin Dependency
In the United States alone, 23.6 million people suffer from diabetes mellitus. Diabetes is the seventh most frequent cause of death in the U.S,, contributing to over 233,000 fatalities per year. Long term risks associated with the disorder include heart disease, stroke, blindness, and kidney failure. Diabetics also have a higher risk of high blood pressure, complications during pregnancy, dental disease, and the need for amputation.
There is no cure for diabetes, and the treatment requires uncomfortable insulin injections. Syringes, insulin pens, jet injectors, or insulin pumps may be used for this purpose. Syringes and insulin pens, which utilize hypodermic needles, and jet injectors, which use a narrow high-pressure jet of insulin, typically require diabetics to give themselves three injections a day, possibly more. Some diabetics knowingly postpone treatment for their condition to avoid painful injections.
An insulin pump can be connected to its user and continuously deliver insulin stored in the pump's reservoir, which can be individually replaced or refilled without having to set up the whole pump again and without the need for additional injections. An insulin pump can also be used in conjunction with a monitor to control the rate of insulin delivery.
Use of Microfluidics for Insulin Pumps
It is advantageous to make these insulin pumps small to minimize patient discomfort and inconvenience. Microfluidics devices are contenders for insulin pumps because they are inherently very small. In addition to portability, actively controlled metering of insulin delivery can be integrated into microfluidic devices.
My research aims to design a microfluidic device with finely controlled insulin delivery. Primary goals include minimizing the size of the device without diminishing the capacity of the insulin reservoir and using an impedance measurement to monitor the insulin flow rate. I will evaluate different metering techniques, including pressure-driven flows (valve-controlled), electro-osmotic flow, peristaltic flow, and piezoelectric flow. In order to measure the flow rate, an impedance detector will be designed. The detector can be greatly simplified if the insulin leaving the reservoir does so in small vesicles of constant size and composition. In this case, the impedance detector would only need to "count" the number of insulin vesicles that pass by it. However, creating the uniform vesicles represents another design challenge.
