FIG. 4.

Toroids are stable building units, whose lumens narrow with predictable kinetics. Toroids were self-assembled and cultured for 48 h before being harvested from the micromolds. Toroids were placed on flat nonadherent agarose and observed for 10 days. Representative bright-field images of toroids self-assembled in recesses with a 600 μm peg diameter and 400 μm circular track width are shown at days 0, 2, 4, 6, 8, and 10 (A–F). Lumen diameter (•, ○) and total diameter (▾, ▿) were measured as a function of time for toroids self-assembled in recesses with a 600 μm peg diameter (closed symbols) and in recesses with a 1000 μm peg diameter (open symbols) (G). Toroid width for the same samples (▪, □) was also measured as a function of time (H). Error bars represent standard deviation. Scale bar is 200 μm.