Multi-Triggered Supramolecular DNA/Bipyridinium Dithienylethene Hydrogels Driven by Light, Redox and Chemical Stimuli for Shape-Memory and Self-Healing Applications

Multi-triggered DNA/bipyridinium dithienylethene (DTE) hybrid carboxymethyl cellulose (CMC)-based hydrogels are introduced. DTE exhibits cyclic and reversible photoisomerization properties, switching between the closed state (DTEc), the electron acceptor, and the open isomer (DTEo) that lacks electron acceptor properties. One system introduces a dual stimuli-responsive hydrogel containing CMC chains modified with electron donor dopamine sites and self-complementary nucleic acids. In the presence of DTEc and the CMC scaffold, a stiff hydrogel is formed, cooperatively stabilized by dopamine/DTEc donor–acceptor interactions and by duplex nucleic acids. The cyclic and reversible formation and dissociation of the supramolecular donor–acceptor interactions, through light-induced photoisomerization of DTE, or via oxidation and subsequent reduction of the dopamine sites, leads to hydrogels of switchable stiffness. Another system introduces a stimuli-responsive hydrogel triggered by one of three alternative signal...