Actin Fluctuations In A Nematic Background

Saturday, October 29, 2011
Hall 1-2 (San Jose Convention Center)
Carlos Perez , Physics, Brandeis University, Waltham, MA
Mark Zakhary , Physics, Brandeis University, Waltham, MA
Zvonimir Dogic , Physics, Brandeis University, Waltham, MA
A theory by M. Dennison of Utrecht University states that the end’s of the polymer, actin, will deviate
from the nematic director to a greater degree then that of the bulk, in a suspension of the fd virus. In order
to either support or refute this theory we suspended actin in a magnetically aligned nematic background
at several different concentrations and measured it deviations from the nematic director. The direction of
the nematic director was found using polscope imagining, which measures the retardance produced by the
nematic fd background. This combined with fluorescence imaging allowed us to measure the deviations
of the actin filaments from the nematic director and determine whether bends in the actin filament are preexisting
or are caused by the nematic background. We expect our results will demonstrate that the average
deviation of the ends of the actin filament will be greater then that of the bulk, thus supporting the theory
proposed by M. Dennison concerning polymers in a nematic background of the fd virus