Effects of engineered nanoparticles on the innate immune system

Abstract

Engineered nanoparticles (NPs) have broad applications in industry and nanomedicine. When NPs enter the body, interactions with the immune system are unavoidable. The innate immune system, a non-specific first line of defense against potential threats to the host, immediately interacts with introduced NPs and generates complicated immune responses. Depending on their physicochemical properties, NPs can interact with cells and proteins to stimulate or suppress the innate immune response, and similarly activate or avoid the complement system. NPs size, shape, hydrophobicity and surface modification are the main factors that influence the interactions between NPs and the innate immune system. In this review, we will focus on recent reports about the relationship between the physicochemical properties of NPs and their innate immune response, and their applications in immunotherapy.

Keywords: Engineered nanoparticle; Immune response; Immunomodulation; Immunotherapy; Physicochemical properties.

Figure 1

Size and shape effect on the innate immune system. a) silica-titania hollow NPs with 50 nm diameter generated more ROS than other size NPs, and generated the highest level of inflammation. b) AlOOH nanorods caused the secretion of more cytokine (IL-1β) than nanoplate and polyhedron in THP-1 cells.

Figure 2

Hydrophobicity effect on the innate immune system. a) TNF-α in vitro gene expression increased with increasing NP hydrophobicity. b) TNF-α in vivo secretion with injection of zwitterionic NPs. NPs bearing a hydrophobic zwitterionic functionality (ZDiPen) boosted LPS-induced inflammatory outcomes, whereas hydrophilic zwitterionic NPs (ZDiMe) generated minimal immunology response.