Related Experiment Video
Updated: May 8, 2026

Combining 3D Magnetic Force Actuator and Multi-Functional Fluorescence Imaging to Study Nucleus Mechanobiology
Published on: July 5, 2022
Note: a portable magnetic field for powering nanomotors, microswimmers, and sensors
P Kinnunen1, B H McNaughton, J Niinimäki
1Fibre and Particle Engineering Laboratory, University of Oulu, 90014 Oulu, Finland.
Abstract:
Time-varying magnetic fields are the basis of many modern devices and are used to remotely power and steer nanomotors and microswimmers. However, the required magnetic field setups are often prohibitively bulky laboratory setups that require technical expertise to build, modify, or relocate. Here we introduce a programmable magnetic field setup based on consumer electronics that is both portable and easy to use. The complete setup consists of a laptop computer, an audio amplifier, and audio inductors and was used to create complex magnetic fields in 0.5-2000 Hz frequency range with up to 4.7 mT amplitude. The setup was also validated using an example application, namely a rotating magnetic field with a constant amplitude and fixed frequency, which has applications in powering nanosensors and microswimmers.
Related Concept Videos
Magnetic Fields
A magnetic field is defined by the force that a charged particle experiences...
Biot-Savart Law: Problem-Solving
Consider a mobile phone battery bank as a source of steady current, which flows through the wire connected between the two. What is the magnitude of the magnetic field created by this current at a field point P?
To estimate the magnitude of the total magnetic field, we first consider a small current element of length dl, at a distance r from the field point. Now the following...
Magnetism
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
Motional Emf
Force On A Current Loop In A Magnetic Field
Energy In A Magnetic Field
Take an ideal inductor with zero resistance. Although it's practically impossible, assume that the coil's resistance is so small that it is practically negligible. The loss of the field's energy to dissipate thermal energy (or heat) is thus negligible.
The energy...
