title: Orthogonal Dual-Triggered Shape-Memory DNA-Based Hydrogels.
abstract: DNA-based shape-memory hydrogels revealing switchable shape recovery in the presence of two orthogonal triggers are described. In one system, a shaped DNA/acrylamide hydrogel is stabilized by duplex nucleic acids and pH-responsive cytosine-rich, i-motif, bridges. Separation of the i-motif bridges at pH 7.4 transforms the hydrogel into a quasi-liquid, shapeless state, that includes the duplex bridges as permanent shape-memory elements. Subjecting the quasi-liquid state to pH 5.0 or Ag(+) ions recovers the hydrogel shape, due to the stabilization of the hydrogel by i-motif or C-Ag(+) -C bridged i-motif. The cysteamine-induced transformation of the duplex/C-Ag(+) -C bridged i-motif hydrogel into a quasi-liquid shapeless state results in the recovery of the shaped hydrogel in the presence of H(+) or Ag(+) ions as triggers. In a second system, a shaped DNA/acrylamide hydrogel is generated by DNA duplexes and bridging Pb(2+) or Sr(2+) ions-stabilized G-quadruplex subunits. Subjecting the shaped hydrogel to the DOTA or KP ligands eliminates the Pb(2+) or Sr(2+) ions from the respective hydrogels, leading to shapeless, memory-containing, quasi-liquid states that restore the original shapes with Pb(2+) or Sr(2+) ions.
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
authors.forename: Xu
authors.initials: X
authors.lastname: Yu
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Kahn
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cecconello
authors.affiliation: Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel. willnea@vms.huji.ac.il.
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
keywords: G-quadruplex; Young's modulus; circular dichroism; i-motif; polymers