| Microsystems targeted for implantation require careful consideration of power, thermals, size, reliability, and biocompatibility. The presented research explored appropriate integration technologies for an implantable drug delivery system suitable for use in mice weighing less than 20 grams. Microsystems technology advancements include in situ pump diaphragm formation; integrated, low volume microfluidic coupling technologies; and incorporation of a low voltage, low-power pump actuation with a zero-power off state. Utility of the developed integration technologies have been tested through in vitro reliability and validation experiments. A four-chamber peristaltic pump was created using micromachining (e.g. thin film deposition and Si etching) and direct write techniques. A novel phase change material based actuator was designed and fabricated to deflect deformable diaphragms into and out of four pump chambers while the diaphragms isolated the pumped fluid from the working material. Polyimide capillary tubing with 140-&mgr;m OD was integrated in-plane and acted as fluidic interconnects to a drug supply and to the pharmaceutical delivery site. Parylene C conformal coating and the design for gap occlusion provided sealed, flexible tubing connections to the micropump. The per chamber actuation power of 10.1 mW at 0.083 Hz resulted in fluid flow of over 100 nL/min with an efficiency of 11 mJ/nL. |
