A Possible New Way to Control Disease: Towards a 24-hour Doctor?

A Possible New Way to Control Disease: Towards a 24-Hour Doctor?

By Mr Ghaz, November 27, 2009

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A Possible New Way to Control Disease: Towards a 24-Hour Doctor?

Many medical conditions can be controlled if patients take regular medication. For example, diabetes.

Diabetes is an illness that occurs when the body fails to produce enough insulin, and enzyme. In healthy people insulin the body breaks down glucose. Without it, glucose builds up to dangerous levels, which can cause coma and even death.

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To prevent this from happening, diabetics must daily make tests of the amount of glucose in their blood or urine and take measured injections of insulin to stabilize their condition. In this way diabetics can lead relatively normal lives. But if the tests are not conducted correctly or if the diabetic misses an injection, problems arise.

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The ideal solution for the diabetic would be to have a supply of insulin implanted into the body and introduced into the blood in regulated amounts as glucose levels begin to rise. Current medical research into devices called biosensors and infusers is trying to achieve such a solution – and not just for sufferers of other diseases as well.

Chemical Care

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Biosensor is the name given to any device that measures biological activity. At the simplest level, a thermometer is a biosensor, since it measures body temperature. Electrocardiograms that measure the heart rate of premature babies and stroke victims, and sound the alarm when dangerous fluctuations occur are a more sophisticated example. But at the forefront of the research are chemical biosensors that can detect the levels of specific substances, such as glucose, in the bloodstream.

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A glucose biosensor for diabetics has been developed by scientists at the University of Michigan. Measuring less than one-fiftieth of an inch across, it can be implanted with little discomfort into the vein of a patient. Shaped like a capsule, the biosensor is connected to the outside of the body by a tiny optic fiber. When a beam of light is directed down the fiber, a dye inside the capsule emits varying amounts of light, depending on the amount of glucose in the blood. Any change in the intensity of the emitted light indicates a change in the glucose level – long before it can be noticed in the usual way by the diabetic or a physician.

Continuous Control

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Accompanying the work on biosensors has been research into infusers – miniature pumps implanted in the body to derive drugs when and where they are needed. Clinical trials of an infuser for diabetics that releases insulin began at the University of New Mexico in 1981. The infuser was controlled by microchip circuits that physicians activated with a small hand-held radio control unit.

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The goal of this research was to develop a “closed-loop” system, in which a biosensor detects a dangerous condition and automatically activates the infuser that corrects it. The doctor would intervene only for routine maintenance and replacement of the implant.

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Pioneering work is also taking place at the University of Washington. The hope: to have an insulin infuser contained in a membrane that will open or close in response to glucose levels and release the required amount of insulin. Such a system would copy the way in which insulin is released into the blood in healthy individuals.

Wider Applications

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Although much of the work on biosensors and infusers was done to benefit diabetics, the principles can be applied to other conditions. High blood pressure could be controlled by a closed-loop system rather than by daily medication.

Cancer patients could benefit too, with infusers delivering controlled amounts of anticancer drugs and painkillers to the sites in which they were needed. This would reduce dosage and help minimize some of the severe side effects that most patients currently suffer.

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For biosensors, other applications suggest themselves. Defective genes could be detected in the earliest stages of pregnancy, for example, while signs of other diseases may be caught long before damaging symptoms appear. Increasingly, an internal 24-hour physician becomes a possibility.