Wirelessly Connected Microimplants Enable Patient-Doctor Communication

Active implants such as brain or heart pacemakers stimulate the nerves by using electrical pulses. Unlike most drugs, they have a direct, local effect and have almost zero side effects as they operate using electrical signals. However, these implants also have some disadvantages. For instance, it is possible for the cable connections between the central implant and the electrodes to break down, and their batteries also need regular replacement. Researchers have now developed a new generation of active, wirelessly connected microimplants that could be implanted in the body for life. In addition to communicating with each other, these implants also allow the patient and doctor to communicate with the network from outside at any time.

Led by the Fraunhofer Institute for Biomedical Engineering IBMT (Sulzbach, Germany), the innovation cluster INTAKT comprising 18 partners from industry, science and the medical sector has developed a network of up to 12 microimplants that can communicate with each other wirelessly, securely and in real time. The tiny assistants that can be implanted in the body could improve the quality of life for people with functional limitations. These miniature assistants can act as a stimulus in patients with tinnitus or digestive tract disorders or help a person’s hand to regain the ability to grip.

Image: The microimplant consists of an eight-layer circuit board (Photo courtesy of Fraunhofer IBMT)

For the INTAKT joint research project, the cluster partners chose delaying or coordinating bowel movements as one of the three areas of application. Gastrointestinal motility disorders, or disorders of movement in the gastrointestinal tract, occur after abdominal surgery in diabetic or paraplegic patients. By placing them at strategic areas in the gastrointestinal tract, each of the implants collect data on the activity of one section of the patient’s system and then sends this information to a central control unit. The unit analyzes the data and instructs the corresponding implants to stimulate the affected part of the intestinal tract, thus ensuring smooth running of the digestive process.

The implants use wireless and infrared signals to interact with each other. However, the problem of energy supply is hindering the development process of the high-tech miniatures. Batteries occupy space and must be replaced regularly. This creates a problem when dealing with a network of implants as each device has different energy consumption levels depending upon their usage. To overcome the problem, the researchers have opted for inductive charging which allows the central control unit to reliably supply the network of implants with energy throughout the day. For emergency situations, the implants include a battery for buffer storage that is also charged regularly via the inductive system.

“The patient can configure their implants to suit their current needs at any time via their laptop or smartphone and optimize their treatment or recovery process in consultation with their doctor,” explained Prof. Klaus-Peter Hoffmann, former head of Biomedical Engineering at Fraunhofer IBMT. “This external energy supply ensures that the implant network will remain stable in the long term. What’s more, the energy supply is adaptive – each individual implant receives the exact amount of energy it needs.”

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