Researchers have long recognized the therapeutic potential of magnetoelectric materials that can convert magnetic fields into electric fields to stimulate neural tissue and treat neurological disorders. The challenge has been that neurons struggle to respond to the resulting electric signals. However, a team led by Rice University neuroengineer Jacob Robinson has developed a groundbreaking magnetoelectric material that not only addresses this issue but also performs the magnetic-to-electric conversion 120 times faster than comparable materials. This achievement, detailed in a study published in Nature Materials, opens up new possibilities for precisely stimulating neurons remotely and repairing damaged nerves.
The implications of this material are significant for neurostimulation treatments. Instead of implanting complex neurostimulation devices, small amounts of this material can be injected at the target site. Moreover, the versatility of magnetoelectric materials extends to computing, sensing, electronics, and various other fields, offering a foundation for advanced materials design that can drive innovation more broadly.
The researchers began with a magnetoelectric material consisting of a piezoelectric layer of lead zirconium titanate sandwiched between two magnetorestrictive layers of metallic glass alloys known as Metglas, which can be magnetized and demagnetized rapidly. When subjected to a magnetic field, the magnetorestrictive element vibrates, leading to a change in shape that generates electricity through the piezoelectric material. This conversion from magnetic to electric fields is a crucial aspect of the material’s functionality.
However, the electric signals produced by most magnetoelectric materials are too fast and uniform for neurons to interpret. To overcome this, the researchers needed to engineer a material that could generate electric signals suitable for cell response. They achieved this by introducing platinum, hafnium oxide, and zinc oxide layers on top of the original magnetoelectric film, thereby creating a nonlinear relationship between the electric and magnetic fields.
The result was a thin layer of less than 200 nanometers, making the entire device small enough for potential injection into the body. As a proof of concept, the researchers used the material to stimulate peripheral nerves in rats and demonstrated its potential for use in neuroprosthetics, showing that it could restore function in a severed nerve.
This breakthrough material not only has the potential to revolutionize neurotechnology but also offers applications in sensing and memory within electronics. Professor Jacob Robinson, inspired by his background in photonics, finds it exciting that they can design devices and systems using materials that have never existed before, opening the door to unforeseen applications beyond the field of bioelectronics.
Source: Rice University