Current technologies that seek to measure the activity of neurons in the brain typically use invasive tethered devices. These types of probes can be cumbersome and have limitations in the number of signals and spatial resolution. Therefore, recent efforts have been focused on compact, completely injectable and untethered wireless devices. Another challenge lies in detecting the magnetic flux density of neuron activity which is 1 nT or lower and rapidly falls to zero within a micron’s distance away. Arrays of superconducting quantum interference devices (SQUIDs) or optically pumped magnetometers can detect fields at 0.1 pT or higher but require synchronous activity from at least ten thousand cells.
New research has been recently reported which seeks to overcome these limitations by the use of a nanofabricated gold electromagnetic coil (nanocoil) to allow the measurement of a small number of neurons in situ in a completely passive, wireless manner that does not require on board power and facilitates remote detection. Detections from the center of the coil can be achieved with room temperature SQUID microscopy and with submillisecond temporal resolution.
The work was reported by Ilhan Bok, Jack Phillips, Tianxiang Zhu, Jennifer Lu, Elizabeth Detienne, Eduardo Andrade Lima, Benjamin P. Weiss, @Alan Jasanoff, and Aviad Hai in a collaborative effort from the University of Wisconsin-Madison and the Massachusetts Institute of Technology. The work was partially accomplished utilizing an STS-Elionix electron beam lithography system.
For more information see https://doi.org/10.1021/acs.nanolett.4c02784
Image (permission use by Aviad Hai and American Chemical Society): (left) Electromagnetic interaction of neuron with nanocoil. (right) Scanning electron micrograph of the gold nanocoil device.