Investigation of a Lorentz force biomagnetometer

Area of Science:

• Physics
• Biophysics
• Instrumentation

Background:

• Noninvasive measurement of small ionic currents is challenging.
• Existing methods may lack sensitivity or be susceptible to noise.
• Biomagnetometry requires sensitive detection of minute biological signals.

Purpose of the Study:

• To evaluate Lorentz force magnetometry for noninvasive measurement of ionic currents.
• To develop and characterize an instrument for detecting low ionic current dipole moments.
• To demonstrate the capability of imaging ionic currents in thin profiles.

Main Methods:

• Constructed a sensitive force-balance instrument to measure Lorentz forces.
• Applied strong oscillating magnetic fields to ionic currents in small objects.
• Scanned a localized magnetic field over specimens to generate and measure Lorentz forces.
• Utilized computer reconstruction to create images of ionic currents.

Main Results:

• The system is sensitive to ion current dipole moments as low as 180 picoampere-meters (pA-m).
• Successfully generated images of ionic currents flowing in thin profiles.
• Demonstrated immunity to ambient magnetic noise.
• The instrument functions as a sensitive force-balance measuring Lorentz forces.

Conclusions:

• Lorentz force magnetometry offers a sensitive approach for noninvasive ionic current measurement.
• The developed technique can image ionic currents in thin specimens.
• The method's noise immunity and sensitivity suggest potential applications in biomagnetometry for small, thin biological samples.