Figure 2. FN-coated paramagnetic beads bound specifically to neurons.

(A) Schematic of the interaction between a superparamagnetic bead, fibronectin and the neuronal cytoskeleton through the recruitment of transmembrane integrins to form a focal adhesion complex. (B) The magnetic bead coating was confirmed by measuring the zeta potential of uncoated beads (control) and FN-coated beads with n = 7 bead reactions per condition. (C) SEM image depicting a FN-coated paramagnetic bead bound to a neurite after beads were seeded onto neurons for 20 minutes. Scale bar = 5 μm. (D) Immunostaining for vinculin (red) and actin (green) revealed focal adhesions at site of bead binding. Scale bar = 5 μm (E) Immunostained image of tubulin in the cell body with a bounded magnetic bead depicted by a red dashed circle. Scale bars = 10 μm. (F) The FN-coated bead is linked to the cytoskeleton through the formation of vinculin-containing adhesion sites that colocalize with the microtubule network. Scale bars = 10 μm.