Figure 4.

Magnetic modulation biosensing system setup. The 532 nm laser beam is reflected by a dichroic mirror and focused by an objective lens onto a borosilicate cuvette, which contains the sample of magnetic beads. The cuvette is positioned between two electromagnets that cause the beads to aggregate and move in a periodic motion, in and out of the laser beam. The laser excites the fluorophores in the sample, and the modulated emitted fluorescence is collected by the same objective lens, filtered by two emission filters, and detected by a camera.