ABSTRACT
Due to their unique properties, carbon nanotubes (CNTs) are being widely explored for industrial and medicalapplications. This has necessitated a thorough assessment of the effect of CNTs on human and animalphysiology and health. Impact of CNTs on epithelial tight junctions has not been evaluated in the context oftheir toxic effects in many biological systems. In the present study, we examined the effect of acid functionalized single-walled carbon nanotubes (AF-SWCNTs) on the function and expression of two tight junctionproteins (ZO-1 and occludin) in the Madin-Darby canine kidney (MDCK) cell line. Treatment of MDCK cellswith AF-SWCNT resulted in a downregulation of tight junction proteins, decreased trans-epithelial electricalresistance (TER), increased paracellular permeability, and disruption of tight junctions. Taken together, ourdata demonstrate that AF-SWCNT disrupts tight junction barrier by downregulating tight junction proteins inMDCK epithelial cells.