First-principles approach to electrorotation assay

We have presented a theoretical study of electrorotation assay based on the spectral representation theory. We consider unshelled and shelled spheroidal particles as an extension to spherical ones. From the theoretical analysis, we find that the coating can change the characteristic frequency at which the maximum rotational angular velocity occurs. The shift in the characteristic frequency is attributed to a change in the dielectric properties of the bead-coating complex with respect to those of the uncoated particles. By adjusting the dielectric proper-ties and the thickness of the coating, it is possible to obtain good agreement between our theoretical predictions and the assay data.