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. Author manuscript; available in PMC: 2011 Jul 20.
Published in final edited form as: Langmuir. 2010 Jul 20;26(14):12003–12011. doi: 10.1021/la1015252

Figure 1.

Figure 1

(A) Absorption of evanescent EM radiation by a fluorescent magnetic bead in water. Evanescent EM field is created by a laser beam undergoing TIR at the silica-water interface. Polystyrene beads are pulled by a magnetic field with a total force F resulting from the interactions (small arrows) between magnetic moments induced in individual magnetite nanoparticles and the magnetic field gradient. (B) The detectable response from the bead fluorescent component – QDs that emit in all directions (arrows) – results from those photons that are transmitted through silica. (C) Geometry of the objective-silica-water-bead setting.