The interplay between nanoparticles and neutrophils

The employment of nanoparticles has markedly increased in recent years for different applications such as aerospace technology, electronics, biology, and medicine. The exposure of nanoparticles to humans is inevitable nowadays. Neutrophils act as the predominant phagocytic cells for first-line defense to be recruited to an inflammatory site against xenobiotics. It is important to explore how neutrophils interact with nanoparticles to elicit immune responses. Different types of nanoparticles have been studied to reveal a potential interaction to neutrophils in vitro and in vivo. These mainly include metallic nanoparticles, polymeric nanoparticles, silica nanoparticles, lipid nanoparticles, and fullerenes. A number of investigations have reported the toxicity of nanoparticles induced by neutrophil activation. In this review we discuss data demonstrating recently recognized aspects of inflammation induced by overwhelmed neutrophils after nanoparticle treatment. Besides the dark side of the nanoparticles, some therapeutic nanoparticles are developed and beneficial in treating neutrophil-related diseases such as acute lung injury, vascular inflammation, and bacterial infection. Some nanoparticles can recruit neutrophils around tumor sites for immunotherapy. We also summarize how nanoparticles actively target neutrophils with therapeutic aims. This review provides a broad introduction to nanoparticle interplay with neutrophils and discusses in vitro and in vivo studies in which they have been evaluated.