title: Switchable bifunctional stimuli-triggered poly-N-isopropylacrylamide/DNA hydrogels.
abstract: DNA-tethered poly-N-isopropylacrylamide copolymer chains, pNIPAM, that include nucleic acid tethers have been synthesized. They are capable of inducing pH-stimulated crosslinking of the chains by i-motif structures or to be bridged by Ag(+) ions to form duplexes. The solutions of pNIPAM chains undergo crosslinking at pH 5.2 or in the presence of Ag(+) ions to form hydrogels. The hydrogels reveal switchable hydrogel-to-solution transitions by the reversible crosslinking of the chains at pH 5.2 and the separation of the crosslinking units at pH 7.5, or by the Ag(+) ion-stimulated crosslinking of the chains and the reverse dissolution of the hydrogel by the cysteamine-induced elimination of the Ag(+) ions. The DNA-crosslinked hydrogels are thermosensitive and undergo reversible temperature-controlled hydrogel-to-solid transitions. The solid pNIPAM matrices are protected against the OH(-) or cysteamine-stimulated dissociation to the respective polymer solutions.
authors.affiliation: Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel).
authors.forename: Weiwei
authors.initials: W
authors.lastname: Guo
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Lu
authors.forename: Xiu-Juan
authors.initials: XJ
authors.lastname: Qi
authors.forename: Ron
authors.initials: R
authors.lastname: Orbach
authors.forename: Michael
authors.initials: M
authors.lastname: Fadeev
authors.forename: Huang-Hao
authors.initials: HH
authors.lastname: Yang
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000138:chemical synthesis* / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D015394:Molecular Structure; D012834:Silver / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D020100:Hydrogels; D007477:Ions; C052970:poly-N-isopropylacrylamide; D012834:Silver; D004247:DNA
keywords: N-isopropylacrylamide; nucleic acids; phase transitions; reversible hydrogels; thermosensitive polymers