Insulin pump

Diabetes mellitus, commonly referred to as diabetes, is a chronic metabolic disorder in which the body's supply of the hormone insulin is disrupted. Shortly after eating, the blood sugar level of healthy people rises because the glucose from the food enters the blood. The insulin causes sugar to be absorbed from the blood into the somatic cells. This lowers the blood sugar level again. By means of the body's control mechanism, the insulin constantly keeps the blood sugar within narrow limits. People who produce no or insufficient insulin or who cannot utilise it suffer from diabetes.

Two different types

Medicine distinguishes between type 1 and type 2 diabetes. The onset of type 1 diabetes generally occurs during childhood or adolescence. These patients produce no insulin in their body. Type 2 diabetes, on the other hand, is caused by a poor diet, overweight and lack of physical activity. Diabetics require insulin regularly to regulate their blood sugar level. Patients who suffer from type 2 diabetes generally only need to take tablets. With serious type 2 cases as well as for type 1 patients, insulin must be injected. In Germany, injection is often performed with the aid of a pen, an injection device that is similar to a fountain pen. In addition to the intake of insulin, the patients must regularly check their blood sugar and learn to estimate the carbohydrate content of their meals in order to calculate the required amount of insulin.

There is, in fact, a relatively recent technological development that should considerably simply life for diabetes patients: the insulin pump. The patient wears this directly on the body. It constantly delivers a small quantity of insulin to the blood; the additional insulin required at mealtimes can be controlled by pressing a button. It does not eliminate the need for patients to estimate their carbohydrate intake, but it is a huge relief for most users in daily life. It is even already in use by small children and can be remotely controlled by parents.

Insulin pumps with micromotor

Though available from various manufacturers, the design of insulin pumps is always similar: an ampoule contains the insulin, which enters the body as needed by means of the battery-operated pump via a catheter and a cannula. A small motor pushes the plug of the insulin ampoule forward via the threaded rod, causing insulin to be released. Extremely high demands are made of the motor: In order to keep down the weight of the wearable device the motor must be compact, and as a rule the diameter must be no more than about 10 millimetres. The motor must be reliable and precise, since too little or too much insulin is harmful to the patient. A human life may even depend on the reliability of the motor that is used. Since the insulin has to be injected into the body every few minutes, the motor must start and stop at regular intervals. In addition, the motor must operate in a very efficient manner due to its battery operation.