  Helical structures like alpha helices, DNA, and microtubules have profound
importance in biology. It has been suggested that these periodic arrangements
of constituent units could support collective excitations similarly to
crystalline solids. Here, we examine the interaction between such constructs
and oscillating dipoles, and evaluate the role of the helicity in the coupling
between electrodynamic fields and vibrations. Based on a vibrational and
eigenfunction analyses we discover a group of modes of coherent oscillations
that give rise to a strong and delocalized response, selectivity in frequency,
and typical interaction range. To describe the field scattering due to the
structure vibrations we consider an anisotropic permittivity with a helical
periodicity, which applies to all vibration types and close dipole locations.
This new type of resonances identified here may help explain the role of
electrodynamic fields in the diverse functionality of cytoskeletal microtubules
in the cellular environment.
