An Fc-directed conjugate (mAb-MNP) of the anti-CD3 monoclonal antibody (mAb), Foralumab, and the surface
amino groups on magnetic nanoparticles (MNPs) was prepared using the SiteClick antibody labeling kit.
The conjugate was imaged by transmission electron microscopy and analyzed using energy dispersive spectrum
and a nanoparticle tracking analyses. The average values of drift velocities (pix/frame) due to the Brownian
motion of MNPs and mAb-MNPs in phosphate-buffered saline were 3.16/0.76 and 6.70/1.98 on the x-/yaxes,
respectively. Two different hydrodynamic diameters of 180.0 nm and 258.8 nm were found for the MNPs
and the mAb-MNPs with an actual size of 35 nm, respectively. The drift velocity was 2 times (2×) higher for
mAb-MNPs than MNPs in proportion to the 2× higher value of the square of the hydrodynamic diameter of the
conjugate relative to the MNPs as calculated by Stokes' law. Thus, the conjugates of Foralumab with MNPs
have better fluidity in PBS than free MNPs.