Abstract The overarching goals of this proposal are to; one, research and develop transparent ultrathin nanomembranes and two, utilize these membranes to advance biomedical in vitro model systems through work in the laboratory of the PI and an array of current and future collaborators. Nanomembrane development will include research towards fabricating ultrathin nanoporous silicon dioxide membranes, scaling up their active area, creating unique surface chemistries to promote cellular interaction and integration of sensor technologies. This proposal will enable collaborators to visualize endothelial barrier transmigration, produce better in vitro corneal models and visualize motile cilia in a patient derived primary lung model of cystic fibrosis. In addition, nanomembrane development through this proposal will enable and supply new collaborators with the tools to solve existing challenges and expand their respective fields. A common need is the ability to culture cells in a physiologically relevant model system that can be visualized in real-time. Transparent ultrathin porous membranes can accomplish this for almost any barrier model and co-culture system. SiO2 nanomembranes enable co-cultured cells to be brought within physiological separations distances (~100 nm), while providing glass-like optical transparency and nearly unhindered transport of signaling molecules. Success in developing new human in vitro systems promises to reduce the reliance on animal models, while simultaneously increasing physiological relevance and accelerating drug development. These tissue- and organ-on-a-chips also make feasible live imaging of complex cellular events that require sophisticated and well-orchestrated microenvironments.