Engineers have created the first neural implant that can be both programmed and charged remotely with a magnetic field. Their breakthrough may make possible embedded devices like a spinal cord-stimulating unit with a battery-powered magnetic transmitter on a wearable belt.
The integrated microsystem, called MagNI (for magnetoelectric neural implant), incorporates magnetoelectric transducers. These allow the chip to harvest power from an alternating magnetic field outside the body. MagNI targets applications that require programmable, electrical stimulation of neurons, for instance to help patients with epilepsy or Parkinson’s disease.
Components of the prototype device sit on a flexible polyimide substrate with only three components: a 2 x 4 mm magnetoelectric film that converts the magnetic field to an electric field, a CMOS chip and a capacitor to temporarily store energy. The team successfully tested the chip’s long-term reliability by soaking it in a solution and testing in air and jellylike agar, which emulates the environment of tissues.