The consequences of particle uptake on immune cells

Particle-based systems are becoming ubiquitous in the clinic. When administered in the body, phagocytic immune cells recognize these particles as foreign substances, resulting in their cellular engulfment for degradation and elimination. However, the internalization of particles may induce unintended effects on the functions of these immune cells. Understanding the consequences of particle uptake on immune cells is imperative to design biocompatible and efficient particulate formulations for diagnostic and therapeutic use. Here, we review the recent literature that describes the changes induced in immune cells following internalization of cargo-free particles. We also discuss how the inherent immunomodulatory properties of particles may be leveraged for therapeutic applications. We conclude with suggestions on newer methods to evaluate the effects of particles on immune cells.