Fig. 4

Catalytic crosslink unlocking enables a signal at concentrations of 100 nM or less to trigger fast, high-degree swelling. a A Catalyst strand unlocks a crosslink via toehold-mediated strand-displacement to form an intermediate unlocked crosslink complex. A Helper strand reacts with this intermediate to release the Catalyst strand, allowing it to unlock another crosslink. b Expansion in response to different concentrations of Catalyst and 10 µM Helper strands added to locked particles pre-incubated with DNA hairpins. Helper strands unlock crosslinks without Catalyst, but much more slowly than with Catalyst. Solid curves are the averages of measurements of 2–4 particles; dotted lines are the individual replicates for each average