We show for the first time that 470 nm thick spider silk membranes support co-culturing of endothelial (HDMEC) and smooth muscle cells (SMC). These cell-silk-cell constructs mimic the wall of small blood vessels. The silk membranes are formed through self-assembly at the liquid:air interface of a standing solution of spider silk protein. We show that the silk membranes enable communication between the cells better than commercial tissue culture inserts (TC-inserts).