Engineered nanoparticles induced brush border disruption in a human model of the intestinal epithelium

Nanoparticles hold great promise in cell biology and medicine due to the inherent physico-chemical properties when these materials are synthesized on the nanoscale. Moreover, their small size, and the ability to functionalize the outer nanoparticle surface makes them an ideal vector suited to traverse a number of physical barriers in the human body. While nanoparticles hold great promise for applications in cell biology and medicine, their downfall is the toxicity that accompanies exposure to biological systems. This chapter focuses on exposure via the oral route since nanomaterials are being engineered to act as carriers for drugs, contrast agents for specialized imaging techniques, as well as ingested pigments approved by regulatory agencies for human food products. After these nanomaterials are ingested they have the potential to interact with a number of biologically significant tissues, one of which is the epithelium of the small intestine. Within the small intestine exists enterocytes whose principal function is nutrient absorption. The absorptive process is aided by microvilli that act to increase the surface area of the epithelium. Dense arrays of microvilli, referred to as the brush border, have recently been shown to undergo disruption as a consequence of exposure to nanomaterials. This chapter aims to set the stage for detailed mechanistic studies at the cell biology level concerning this newly emerging nanotoxicity research paradigm, as the underlying structural characterization responsible for the existence of microvilli have been elucidated.