Margination of Micro- and Nano-Particles in Blood Flow and its Effect on the Efficiency of Drug Delivery

Abstract

Drug delivery by various micro- and nano-carriers offers the possibility of controlled transport of pharmaceuticals to targeted sites (e.g., cancerous tissue). Even though the fabrication of carriers of different sizes and shapes with a number of functionalities has made much progress in the last decade, their delivery including controlled particle distribution and adhesion within the body remains a great challenge. The adhesion of micro- and nano-carriers in blood flow is strongly affected by their distribution within the vessel cross-section. To investigate the adhesion potential of carriers of different shapes and sizes, we employ mesoscopic hydrodynamic simulations of blood flow in order to predict margination of carriers or their migration properties toward vessel walls. The margination of carriers is studied for a wide range of hematocrit values, and flow rates, using a two-dimensional blood-flow model. Two different particle shapes (spherical and ellipsoidal) and various sizes, ranging from about hundred nanometers to several micrometers, are considered. We find that the margination properties of particles worsen with decreasing carrier size. Spherical particles yield slightly better margination than ellipsoidal particles; however, adhesion of ellipsoidal carriers is expected to be superior due to a larger area for adhesive interactions. As a conclusion, micron-size ellipsoidal particles seem to be favorable for drug delivery in comparison to sub-micron particles and spherically shaped carriers.