Phagocytosis independent extracellular nanoparticle clearance by human immune cells.

It has recently been discovered that human immune cells, especially neutrophil granulocytes, form neutrophil extracellular traps (NETs) that abolish pathogens. Our study provides evidence that extracellular traps formed by neutrophils, monocytes and macrophages act as physical barriers for nanoparticles, thus presenting a new nanomaterial clearance mechanism of the human immune system. While particle shape is of minor importance, positive charges significantly enhance particle trapping.