Electroceuticals are microimplants equipped with electronic solutions that use electricity to provide personalized and localized treatment without causing side effects in the body. Researchers at Fraunhofer IZM have now taken a new approach and are using ultrasound instead of electricity.
Ultrasound waves are pressure waves that are applied externally, penetrate the body and thus reach the implant. There are clear advantages compared to conventional battery-operated devices: Ultrasound can be used to charge the implants from the outside, making invasive procedures or wired charging obsolete. Above all, the extreme miniaturization of the systems is an innovation in the field and enables the microimplants to precisely stimulate nerves as small as 20 micrometres.
By using ultrasound to charge the implants, the team at Fraunhofer IZM has found a solution for efficient energy transfer, one of the biggest technological challenges in medical technology. This is because built-in batteries have so far made miniaturization difficult, with energy depletion being unavoidable and thus requiring replacement, i.e. a further surgical procedure. In addition, battery-powered implants equipped with induction coils can only be inserted close to the skin.
In contrast, the smallest ultrasound transducers make it possible to use the microimplants of the future far inside the body. When high-frequency sound hits them, they start to vibrate. These tiny movements are converted into electrical energy for the microimplant. The challenge is to optimally align the vibrating microstructures in order to avoid high losses during energy transmission. At the same time, only extremely small structures can be used, as the overall size of the implant must not exceed a few millimetres.
