Schematic representation of the transwell permeability assay. The system consisted of two chambers (apical [AL] and basolateral [BL] sides) separated by a porous membrane. Caco-2 cells were cultured and differentiated in the upper chamber (AL side). The peptides were added to the AL side (for further details, see Supporting Information [SI]). The zoomed part shows schematically the apical localization of ZO-1 (for experimental details see SI).
