Subcellular magnetic imaging of living cells
May 1, 2013
In their study, they use “magnetotactic” bacteria (MTB), which contain magnetic nanoparticles.
The researchers, David Le Sage, David Glenn, and Ron Walsworth, together with their collaborators, place these live bacteria onto a diamond surface that has been modified to contain crystal defects that interact with magnetic fields and with light.
By shining a laser beam onto the surface and measuring the pattern of the light emitted by the defects, using an optical microscope, they are able to record images of the magnetic field pattern present at the diamond surface with a spatial resolution of ~400 nanometers (the wavelength of violet light).
The technique is a spinoff from the group’s laser-technology research on behalf of astronomical research, including exoplanet detection and radio interferometry.
These first results demonstrate the promise of the technique to probe magnetically the internal structure of living cells. This technique could be used to shed new light on the properties and life cycles of these magnetic bacteria, and it points the way toward more sophisticated probes of a wide range of other biologically interesting systems, the researchers say.
“The ability to locate chains of nanoparticles from the magnetic images will make it possible to measure the movement of magnetosome chains across the cell-division cycle of individual MTB,” the researchers say in the Nature paper. “The measurements … are also directly applicable to studying the formation of magnetic nanoparticles in other organisms. Such formation is of interest for MRI contrast enhancement, and has been linked with neurodegenerative disorders; it has also been proposed as a mechanism for magnetic navigation in higher organisms.”