Fig. 2.
Experimental design and gel results. a The programmed assembly sequences of the fluorescently labeled droplets used in this study. b The toehold strand displacement in each step corresponds to the sequential binding of droplets and their progressive activation of droplets in a. c Native PAGE demonstrates the step-by-step toehold strand displacement reactions depicted in b. Column ‘10 bp ladder’ is the marker lane. Column S0 serves as a reference for single strands S2, S4, and S6 with the similar molecular weights. Similarly D1 is a reference for D2 and D3 (completely hybridized duplex strands); L1 is a reference for L2 and L3 (partially hybridized strands), while S7 and D4 mark the terminator hairpin strand and its partially hybridized duplex strands. Columns S0 + L1 → D1 + S2, S2 + L2 → D2 + S4, S4 + L3 → D3 + S6, and S6 + S7 → D4 show that the reactions depicted in b produce the desired results and leave none of the initial reactants. Column L1 + L2 + L3 + S7 shows that the partially hybridized protected strand pairs are inert. The final column shows that the reactions go to completion when the initiator is added