There has been a growing interest in using micro- and nano-particles as drug carriers, especially for cancer treatment (1). However, little is known about the rheology of particles in blood flow, which must be understood if the drug-carrying particles are to be administered intravenously. Decuzzi et al.
and Graham et al.
(2, 3) showed in their modeling that particles can undergo a "margination" phenomenon wherein the particles trend toward the periphery of blood vessels. The implication is a higher chance for the particles to diffuse into the tumor through the leaky vasculature typically found near tumor sites. Experimentally, most existing studies use particle adhesion to channel walls during flow as a mechanism for quantifying the margination propensity of particles. However, adhesion is also affected by other factors, such as hydrodynamic drag and ligand density, further complicating the interpretations of experimental results (4). In this presentation, we will present our findings on directly tracking the spatial distribution and velocity of particles flowing through microfluidic devices. A margination parameter, M
, is further defined as the total number of particles found within the cell-free layers normalized by the total number of particles that passed through the channel. The effects of particle size, suspending medium, and apparent shear rate on margination propensity were quantified using this parameter.
1. Davis, ME. Fighting cancer with nanoparticle medicines―The nanoscale matters. MRS Bulletin. 2012;37:828-835.
2. Decuzzi P, Lee S, Bushan B, Ferrari M. A theoretical model for the margination of particles within blood vessels. Annals Biomed. Eng. 2005;33(2):179-190.
3. Kumar A, Graham MD. Margination and segregation in confined flows of blood and other multicomponent suspensions. Soft Matter. 2012;8(41):10536–48.
4. Carboni E, Tschudi K, Nam J, Liu X, Ma A. Particle margination and its implications on intravenous anticancer drug delivery. AAPS PharmSciTech. 2014;15(3):762-71