Confluent Caco-2 monolayers grown on transwell inserts were incubated with 125I-anti-ICAM NCs or 125I-IgG NCs added to the apical chamber. (A–C) 125I content in the basolateral chamber was measured at the indicated time points, to calculate the amount of NCs transported per cell (see Representative Results). (B) Percent of transported NCs was calculated as the ratio of carriers found in the basolateral fraction to that in the combined basolateral and cell fractions. (D) Apparent permeability coefficients (Papp) were calculated as described in Representative Results, reflecting rates of transport of 125I-anti-ICAM NCs or 125I-IgG NCs. Data are shown as means ± S.E.M; n=4. Reproduced from Ghaffarian et al., J Controlled Rel, 2012, 163(1):25–33.