There is and it is called a drug pump. It is implanted in the body and using a LED sensor can measure glucose. This then can tell the device to give insulin or not 24/7. They are working on this design because I have seen it first hand. I do not know of any FDA approval of a design but you could Google Medtronic drug pump. They are the largest medical company in the world. I designed Cardiac Pacemakers with St. Jude Medical Inc. the third largest medical company in the world.
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Regards, Maveric Manic - 'Knowledge is Power and Wisdom is knowing how to use it'