Toxicological mode of action of ZnO nanoparticles: Impact on immune cells

•Effect of size and shape of ZnO nanoparticles on cytotoxicity.•ZnO nanoparticles dissolution may be the causative factor for toxicities.•Mechanism of ZnO nanoparticles internalization and subsequent effects.•Inflammatory responses and antigen presenting cells dysfunction by ZnO nanoparticles.

The use of nanoscale materials is growing exponentially as concerns rise about the human hazards to it. It is assumed that living beings are coevolved with nanoparticles ever since the origin of life on earth and therefore, they must have developed the defense and toxicity mitigating mechanisms for nanoparticles. Although having peculiar properties these new materials also present new health risks upon interacting with biological systems. Zinc oxide is the most widely used nanoparticles among various nanomaterials. Recently, these nanoparticles have been shown to specifically kill cancerous cells; therefore, it is believed that these nanoparticles may be used as an alternative anti-tumor agent. However, it is also known that these nanoparticles pose several deleterious effects to living beings. It is therefore critical to understand the nature and origin of the toxicity imposed by these nanomaterials. Keeping these points in mind the present review provides updated information on various aspects of toxicities induced by these engineered nanoparticles.

Graphical abstractOverview of ZnO nanoparticles biodistribution and its toxicological mode of action.Figure optionsDownload full-size imageDownload as PowerPoint slide