Fig. 1: Tunable gel polymerization (growth) and depolymerization (shrinking) directed by DNA sequence activators.
From: Programming gel automata shapes using DNA instructions
a Schematic of DNA-directed polymerization gel growth and shrinking. Sequential insertion of hairpin-shaped growth activators drives polymerization at crosslinks, and thus, the growth of DNA gels. The shrinking activators drive depolymerization at crosslinks, and thus, DNA gel shrinking. Black dots indicate where DNA is attached to the base polymer (e.g., polyethylene glycol). Brown dots indicate chemical crosslinks. DNA domains (structures that end with arrows) with the same colors are identical or complementary DNA sequences. Scale bar, 1 mm. b Four designed and selective DNA polymerization/depolymerization systems. Differently colored squares [System I (blue), System II (red), System III (yellow), and System IV (purple)] represent hydrogels with different DNA crosslink sequences. DNA activators of each color induce growth and shrinkage of the corresponding (same-colored) hydrogel region. c Schematic of DNA polymerization mechanism. d Schematic of DNA depolymerization mechanism.
