  We propose a model to explain finite-size effects in intracellular
microrheology observed in experiments. The constrained dynamics of the
particles in the intracellular medium, treated as a viscoelastic medium, is
described by means of a diffusion equation in which interactions of the
particles with the cytoskeleton are modelled by a harmonic force. The model
reproduces the observed power-law behavior of the mean-square displacement in
which the exponent depends on the ratio between
particle-to-cytoskeleton-network sizes.
