FIG. 1.

Overview of multi-channel collagen-membrane gas exchange devices. (A) Three-dimensional schematic of a multi-channel collagen-membrane device, showing the assembly of the lower channel layer, collagen membrane, and parenchymal/air chamber layer. Blood flow is indicated by the dark arrows; airflow is indicated by the light arrows. Blown-up detail shows orientation of the collagen membrane and vascular channels (channels not to scale). (B) Overhead schematic of vascular channels with overlaid collagen membrane and air chamber to demonstrate alignment (channels not to scale). (C) Transmission electron microscopy (TEM) showing detail of collagen membrane [C] in tissue-engineered alveolus with A549 lung carcinoma cell [P]. (D) Comparison between thicknesses of collagen membranes produced using different collagen concentrations. **p<0.01.