Safety of Zein Nanoparticles on Human Innate Immunity and Inflammation

In recent years, natural polymers have attracted great interest for the development of release systems for vaccine formulations and drug delivery. Zein, a hydrophobic proline-rich protein mixture obtained from maize, is one of the most widely used polymers, very promising for applications in tissue engineering and the parenteral delivery of bioactive agents. Still, we have a limited understanding of the interaction between zein particles and the human immune system, in particular innate immunity/inflammation, which is the first line of defense of our body. Assessing the immune safety of nanoparticles is of central importance for ensuring that nano-formulations for medical use do not cause adverse effects on human health. Here, we evaluated the capacity of zein nanoparticles to induce/modulate the innate/inflammatory response, the development of innate memory, and the macrophage polarization by using reliable in vitro systems based on human primary monocytes and monocyte-derived macrophages. We observed that zein nanoparticles do not influence any of these aspects of the innate immune/inflammatory response, suggesting its safety and its potential efficiency as a nanocarrier for drug or antigen delivery.