Jack and
DNA stalk


Molecular actuator has attracted much interest in nanorobotics fields.
Recently, researchers have succeeded in demonstrating “polymerization actuator” that can change its length dramatically by DNA hybridization chain reaction (HCR). When both ends of the actuator by HCR are anchored between the objects, because it extends keeping its crosslinking point, it can extend the distance between them. By applying this system for crosslinks between hydrogels, researchers achieved 100 times gel swelling.
However, there is a problem that shrinking of the actuator is improbable because HCR is driven by enthalpy gap of polymerization of DNA hairpins, HCR material. Here, we propose a novel shrinking mechanism of the polymerized actuator, called “reversible HCR”.Our designed actuator can remove DNA while keeping its crosslinking point, carried out by the “irreversible process” with hairpin DNAs for its shrinking.
Based on our system, we may develop a molecular actuator that can both extend and shrink.