Problems in the ferroelectric model of microtubules
The biophysical aspects of microtubules are the most important issue in direct
relationship with microtubular sensitivity to the external electric field (Trpisova &
Brown, 1998; Faber, 2003; Brown & Tuszynski, 2003). Brown & Tuszynski (1999)
model the microtubules as ferroelectric cylinders and consider that the tubulin
dimer has dipole moment that could be in up and down position. In the up
position is supposed that the dipole is collinear with the z-axis however when it is
in down position the dipole forms angle φ~29o with the z-axis. The ferroelectric
model is considered to be improved version of the cellular automaton model
developed by Hameroff et al. (1988) where a discrete charge is associated with
each tubulin dimer and can either be localized in the top monomer (α state) or
bottom monomer (β state) (Tuszynski et al., 1998).
Fig. 18 Dipole moment of the tubulin dimer as considered in the original paper of
Brown & Tuszynski (1999): (a) tubulin dimer dipoie; (b) microtubule cross-section
with attached coordinate system.
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