Self-assembly and chains of rotating magnetic particles

Self-assembly and chains of rotating magnetic particles: The experimental set-up consisted of three simple components: a light source of a non-polarized white beam, a cuvette containing a solution of functionalized magnetic beads, and a compact spectrometer. The biotinylated magnetic beads used by the researchers had a diameter of 250 nm, and consisted of superparamagnetic particles embedded into a polymer matrix. The polymer surface was covered with biotin biomolecules and the concentration of avidin added to the solution was measured by applying a rotating magnetic field to the cuvette and monitoring optical transmission of the solution when the target molecule (avidin) was added to the solution.