"Our method uses magnetic fields to slow the flow of particles through tiny glass tubes called capillaries," Williams explained. "We use a magnet to pull magnetic particles against the wall of the tube and, when the magnetic field is reduced, the particles flow out of the capillary. Magnetism increases as particle volume increases, so small and gradual changes in the magnetic field let us slowly separate and distinguish between nanoparticles based on even minute magnetic and structural differences."
The team's paper shows how magnetic fields can be used to separate and distinguish between hybrid nanoparticles in a mixture of slightly different structures and shapes. In one example, the researchers separated "nano-flowers," so named because of their petal-like arrangement around a solid core, from spherically shaped particles. Williams explained that the magnetism of the particles depends on their shape, so particles of a different shape adhere to the capillary wall when different magnetic fields are applied, thus allowing the researchers to distinguish between the different particles.
In another example in the paper, the researchers showed how the magnetic-field method can be used with a class of nanoparticle dubbed the "nano-olive," which is a spherical particle comprised of two different materials joined in a shape reminiscent of an olive. The nano-olives, which are composed of iron, platinum, and oxygen, may look alike, but they may have slightly different internal compositions that are impossible to detect under a microscope. "For example, some may have more iron content," Schaak explained. "This is a property we can use for
|Contact: Barbara Kennedy|