Biomagnetic field detection using very high sensitivity magnetoimpedance sensors for medical applications

Abstract

This paper demonstrates the performance of magnetoimpedance (MI) sensors for biomagnetic field recording. The rms noise of an amorphous wire MI sensor with 600 turns of pick‐up coil was estimated as approximately 3 pT/Hz1/2 at 1 Hz. Here, we demonstrate that this sensitivity is enough to clearly detect magnetic cardiogram signals. We also measured the biomagnetic field around a smooth muscle tissue sample taken from a guinea‐pig. We discovered that the magnetic‐field waveform of a small tissue sample is similar to the voltage waveform measured by a microelectrode array in a smooth muscle sheet sample. The results suggest that the localized biomagnetic field generated by smooth muscle cells can be detected by an MI sensor. We concluded that the MI sensor is a promising device for use as a noninvasive tool to test cell activity or function through magnetic‐field measurement. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study

“…The magnetoimpedance sensor can detect 50 pT magnetic fields without shield room. 29 In a pilot study, using an magnetoimpedance sensor, we found that exposure of humans to our ELF-EMF for 10 min altered their blood flow. Subjects were a 68-yearold male and female who were exposed to 10 min ELF-EMF.…”

Electromagnetic sensor technology for biomedical applications

“…The GMI sensor based on C-MOS IC with a pair of amorphous wires for differential output was successfully applied for measurements of biocell magnetic fields Uchiyama et al, 2009). This kind of detection can be developed to become, for example, an organ prediction method for iPS cell growth.…”

New methods for probing and exploring magnetoelastic properties of amorphous ferromagnetic alloys

“…Additionally, the ribbon may be coated with functional materials, such as catalysts, chemical, or biological sensors, opening the door for a large spectrum of sensor applications. [1][2][3][4] In this work, we present two new approaches to probing and exploring the magnetoelastic coupling in amorphous ferromagnetic alloys. One method involves mechanical vibration of a ribbon while sensing its electromagnetic response.…”