  In this work a Lattice Boltzmann Immersed Boundary method is used for
predicting the dynamics of rigid and deformable adhesive micro carriers (1 um)
navigating a capillary by the size of 10 um with 20% hematocrit. Red cells and
particles are modeled as a collection of mass spring elements responding to a
bending potential, an elastic potential and total enclosed area conservation
constraint. Furthermore, particle surfaces are uniformly decorated with
adhesive molecules (ligands) interacting with receptors disposed on the walls.
Particle adhesion is modeled as a short range ligad receptor interaction and in
term of formation and destruction probability functions that discriminate
whether a chemical bond can be formed or destroyed. If a bond is established an
attractive elastic force is activated. Particle transport and adhesion are
characterized in terms of their ability to reach the capillary peripheries
(margination rate) and firmly adhere the vasculature. This analysis is carried
out systematically by varying particles' and cells' releasing positions and
stiffness (Ca = 0 and 10-2). Moreover, three rigid and soft representative
particles are transported on a finer mesh (Dx = 15 nm) and the chemical
strength of their adhesive coating is varied (s = 0.5, 1.0, and 2.0) to
precisely analyze the resulting adhesion mechanics. Stiffness is found to
weakly influence the margination rate while significantly affect the ability of
such constructs to efficiently interact with the endothelium by forming stable
chemical bonds.
