Documents / Report
This Defense Intelligence Agency reference document, dated 31 March 2010 (DIA-08-1003-020), was one of a series of advanced technology reports produced in FY 2009 under the Advanced Aerospace Weapon System Applications (AAWSA) program. It surveys biosensors and BioMEMS, covering brain-implanted neuroelectrodes, drug-delivery pumps, implantable glucose sensors, brain-machine interfaces, retinal prostheses, microfluidic lab chips, NASA cell culture systems, and microcantilever sensors. It concludes that the field is expanding rapidly toward nanomechanical systems.
UNCLASSIFIED/,'F8A 8FFliIAk Wi&i &•lb¥ So far, despite decades of work, no continuous monitoring sensor that is self contained and implantable has been successful for long term usage. The human body is an exceptionally hostile environment for foreign materials. Even our most advanced biosensors fail over a period of days or weeks if continuously exposed to the body environment. This failure is mostly due to the sensor chemistry wearing out in one way or another or attack of the sensor interface by the body's immune system. Failure is not generally attributed to the materials of which the sensor is made. MEMS Blood Glucose Sensors Diabetes is an enormous world problem. A significant fraction of the annual world health care expenditures can be traced back to diabetes, and its cousin, obesity. Measurement of blood glucose on a regular basis, usually 3-4 times a day, allows a diabetic to regulate his diet and insulin dose to achieve normal glucose levels. Perhaps one of the most needed biosensors is that for an in-vivo blood glucose sensor. These could be used to automatically control of the output of an insulin-delivery pump. This would constitute a major improvement in the treatment of diabetes by automatically using blood glucose concentration feedback to stabilize the blood glucose levels with the exact level of needed insulin. This kind of system is sometimes called an artificial endocrine pancreas since it mimics the normal function of the pancreas in regulating insulin release. There are several attempts at using MEMS devices to produce indwelling glucose sensors. These are presently on the market, but currently the sensors have relatively short lifetimes, are disposable, and require replacement every few days. Figure 9 shows this basic idea. An implantable sensor produces an electrical output that reports the blood glucose concentration. Its signal is transmitted to a receiver and then processed by a computer to drive a belt-worn pump. The creation of such a sensor has been a daunting problem from more than 30 years. The most recent attempts have been in the use of micromachining to produce optical devices of very small size and to produce wireless transmitting electrochemical sensor devices small enough to be injected into the body. Coincident with the development of - GluCOH Hnaot' 2 Figure 9. Control of an Insulin-Delivery System by an Implantable Glucose Sensor (Medtronic Inc.) sensors has been the need to develop very small wireless telemetry systems that transmit the sensor data to outside the body. 13 UNCLASSIFIED/ ,'P8"1 8PPll!l"'I! l!l!il! 8111!1f
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 45 pages are in the text index: search them above, or from the library's search.