We previously discovered that the main component of bacterial cell membranes, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), self-assembles into single-wall tubes with an outer diameter of 19.1 ± 4.5 nm and a length of close to 1 mm (synthetic lipid nanotubes, LNTs). 1By exploiting the interaction of living cells (REF52) with LNTs, we demonstrated cell contractility recording. The newly generated LNTs pattern upon cell spreading exhibited structural fingerprints characteristic for cell types and conditions. Monitoring the fluorescent-labeled LNTs and paxillin accumulated at the focal adhesions of fibroblasts simultaneously, we proved that the nucleation of new LNTs is linked to the cell's focal adhesions and contractile activity.Tunneling nanotubes (TNTs) are tube-shaped cell membrane structures between cells.2 The characterization of TNTs' functionality by traditional biological approaches often suffers from the complexities and a lack of controllability in the connection. We developed synthetic TNTs by connecting cells with the LNTs as a model system to investigate this new cell-cell communication tool. Cells (REF52 and PC12) were rinsed with physiological buffer solution to remove associated proteins, and seeded on surface-patterned LNTs. Dye-tagged phospholipids incorporated in the LNTs diffused into the cell plasma membrane, suggesting the fusion between the LNTs and the cell membrane. Physical parameters (e.g. temperature, osmotic pressure) were optimized to promote the fusion efficiency. TNTs were found to mediate the calcium wave propagation in different cells types. It implies that the inter-cellular calcium migration does not require the direct cell-cell contact with formation of gap junctions but occurs remotely through TNTs over much longer distance. We study this TNT-mediated calcium propagation by fabricating several artificial TNT-cell circuits of different geometries.1. K. Sugihara, et al., ACS nano 6, 6626 (2012).2. A. Rustom, et al., Science 303, 1007 (2004).