Fig. 3
Visualization and quantification of translocated DEPs into the basal fraction across porous PET membranes. (a) TEM images of the translocated DEPs across 0.4, 1.0, and 3.0 μm porous membrane collected from the basal cell culture medium. The applied concentrations of the DEPs on the apical side of the membrane are 0, 0.1, 2.0, 20, and 80 µg mL−1 in MQ-Curosurf solution, scale bar: 0.5 μm. (b) and (c) Percentage of translocation of DEPs across 0.4, 1.0, and 3.0 μm porous membrane determined with ultraviolet–visible (UV–Vis) absorbance spectroscopy (b) and lock-in thermography (LIT) (c). The means ± SD from three independent experiments were used as technical replicates (n = 3). ** represents (p < 0.01), *** (p < 0.001), **** (p < 0.0001)