Abstract
Magnetoelectrics are a class of material defined by their highly efficient conversion of magnetic fields to electric fields and vice versa, which have a wide range of potential applications. In biological contexts, electric fields not only influence the nervous system, but they can also increase drug uptake, induce behavioral changes, and even initiate cell death. Thus, a material that can convert non-tissue-interacting magnetic fields into biologically significant electric fields, and vice versa, could have serious implications in medicine. The work presented here covers the development of nanoparticle versions of magnetoelectric materials and the adaptations necessary to use them in biological contexts, the creation of a new form of neuromodulation based on that material, and the demonstration of that neural stimulation in in vitro and in vivo studies up to primates.
In this work, magnetoelectrics are fabricated at the nanoscale, using a core – shell morphology based on magnetostrictive and piezoelectric composites. Using a new, nanoscale approach to magnetoelectric (ME) effect measurement we developed, we show that the particles have ME effects two orders-of-magnitude higher than previously reported. The magnetoelectric nanoparticle (MENP) fabrication process is then optimized to produce nanoparticles that satisfy several critical criteria for biological applications, including high biocompatibility, blood-brain barrier transference, and controllable uptake time. The MENPs produced by this method have demonstrated the first ever wireless, minimally invasive neuromodulation method with spatiotemporal behavior on par with established wired electrode stimulation methods, all without genetic modification. The fundamental work here shows how to create MENPs that are useful in biological contexts, and the approach described here can be tuned to create custom MENPs for any number of biological tasks.