Depletion interactions of non-spherical colloidal particles in polymer   solutions
  We consider anisotropic colloidal particles immersed in a solution of long, flexible, and nonadsorbing polymers. For the dumbbell shapes of recently synthesized particles consisting of two intersecting spheres and for lens-shaped particles with spherical surfaces we calculate the isotropic and anisotropic interaction parameters that determine the immersion free energy and the orientation-dependent depletion interaction between particles that are induced by the polymers. Exact results are obtained for random-walk like (ideal) polymer chains. 
E. Eisenriegler and A. Bringer