(25) Using inhibitor KPT-330 this system the intracellular localization of titanium dioxide nanoparticles was analyzed by energy filtering transmission electron microscopy.(26) Titanium dioxide NPs were detected as single particles without surrounding membranes and in membrane-bound agglomerates. The triple cell coculture incubated with titanium dioxide particles also showed an elevated production of reactive oxygen species but no increase of the release of tumor necrosis factor alpha. The interplay of different lung cell types seems to substantially modulate the oxidative stress and the inflammatory responses after NP exposure.(27) Our recent studies have also shown that fluorescent-magnetic hybrid NP-induce increased pro-inflammatory responses in airway epithelial cell cultures; on the other hand, gold NPs did not cause adverse effects.

(28,29) These studies suggest that particulate characteristics and cell culture models may have substantial impact on the cellular responses. The cellular responses may further be modified by disease states of the donors and the environmental stresses and need to be evaluated.(30,31) With this aim we designed this study to investigate cellular deposition and delivery in normal and diseased airway epithelial cell culture models. In the current study NPs were exposed to cells at ALI that resemble in vivo exposure conditions of the lungs more realistically than under submerged conditions and allows a controlled deposition of aerosolized NPs.(32) The use of 3.6��106 particles/cm2 which corresponds to 0.

1mg/cm2 is considered to be in the realistic range as recommended by Occupational Safety and Health Administration standard.(32) However, in the present study the administration of the polystyrene NPs was done with the PennCentury microsprayer?, and with this system it is only possible to deliver the dose within a very short time, that is, few seconds. This does not correspond to the in vivo situation where an aerosol is inhaled over time. Several air�Cliquid exposure systems are meanwhile described in the literature such as CULTEX or the ALICE, and with those devices it is possible to apply an aerosol over time, that is, mimicking again a more realistic situation.(33�C35) For future studies such more sophisticated systems are planned to be applied. We also evaluated ozone, an important environmental factor, for its potential effects on modulating the NP delivery and response of airway epithelial cells.

We demonstrate that ALI cultures of non-CF and CF airway epithelial cells accumulate increased Dacomitinib quantities of synthetic NPs. Flow cytometry data revealed increased fluorescence in the CF cell lines, suggesting enhanced particle uptake. This could be due to CFTR dysfunction that may contribute to decreased vesicular exocytosis. Inhibition of exocytosis and accumulation of antibiotics has been shown previously in the epithelium of nasal polyps in CF patients.