Figure 2.

Condensate patterning is predictable and customizable. (a–d) Patterning-strand scheme (-i) and equatorial confocal microscopy sections (-ii) for condensates patterned to form an increasing number of concentric domains, from one in system a to five in system d. Some patterning strands are fluorescently labeled with Alexa 594 (p1) and Alexa 488 (p5 and p8) while others do not bear modifications, resulting in dark regions intermitting the fluorescent shells in the confocal data. See Table S1 for the DNA sequences. The spatiotemporal evolution of the domain structure is visualized as the azimuthally averaged, normalized radial intensity profile I(r, t), where r is the radial coordinate defined from the centroid of the condensate and t is the time elapsed from exposure of the condensates to the patterning strands (-iii). For systems a–c, I(r, t) is compared with the fitted outcome of a reaction–diffusion numerical model (-iv). Note that early times are not shown in experimental color maps (gray bands) due to a delay between the time at which condensates were exposed to the patterning strand (t = 0) and the start of the confocal recording. See the Experimental Methods (SI) for information on image analysis and numerical modeling. For system d, subpanel d-iv shows the radial intensity profiles extracted from confocal images at t = 7 min, highlighting the presence of five distinct domains. The green dotted and red dashed lines mark the signals from the Alexa 488 (p5 and p8) and Alexa 594 (p1) channels, respectively, while the black solid line represents the overall intensity. All profiles are normalized by their highest value. (e) Domain propagation can be arrested by adding an excess of the stop strand (s) in solution (e-i, see also Figure 1a), as demonstrated in e-ii with confocal data for a system with three patterning strands (p1, p6, and p8). The stop strand was added at t = 16 min, after which no further pattern evolution was observed (besides photobleaching). Videos S1–S8 show the pattern evolution in individual condensates (even numbered) and larger fields of view (odd numbered). See the supplementary videos key in the SI. Scale bars represent 15 μm.