Supplementary Video 1 Fibroblast Self-Assembly

Fibroblasts quickly adhere to one another and self-assemble around an agarose peg to form a toroidshaped engineered tissue construct. Monodispersed normal human dermal fibroblasts (NHDFs) were seeded in an agarose gel and imaged over 24-48 hours. Cells quickly adhered to one another and contracted around the agarose peg. As cells exert forces on one another, cell-mediated tension develops circumferentially around the agarose peg.