This document provides a protocol for rapid, quantitative measure of the chemoattractant capacity of a nanoparticulate material. Leukocyte recruitment is acentral component of the inflammatory process, both in physiological host defense and in a range of prevalent disorders with an inflammatory component. In response to a complex network of pro inflammatory signaling molecules (including cytokines, chemokines and prostaglandins), circulating leukocytes migrate from the bloodstream to the site of inflammation.