2.11 Permeability monitoring of alveolar-capillary barrier on the chip
The permeability of the alveolar-capillary barrier on the chip was assessed by measuring the diffusion rate of FITC-dextran (40 kDa, purchased from Thermo, USA) from the upper vascular layer to the lower alveolar compartment. Following smoke exposure, media with FITC-dextran were added to the upper channels. Samples from the lower chambers were collected at set intervals (0 and 60 min), and their fluorescence intensities were measured with a plate reader. This rate was computed to ascertain barrier permeability. Real-time observation of fluorescence in the lower layer was also performed to assess permeability through the chip’s transparent sections.