title: Electrochemically stimulated pH changes: a route to control chemical reactivity.
abstract: A bis-aniline-cross-linked Au nanoparticle (NP) composite is electrochemically prepared on a rough Pt film supported on a Au electrode. The electrochemical oxidation of the bis-aniline units to the quinoid state releases protons to the electrolyte solution, while the reduction of the quinoid bridges results in the uptake of protons from the electrolyte. By the cyclic oxidation of the bridging units (E = 0.25 V vs SCE), and their reduction (E = -0.05 V vs SCE), the pH of the solution could be reversibly switched between the values 5.8 and 7.2, respectively. The extent of the pH change is controlled by the number of electropolymerization cycles applied to synthesize the Au NP composite, demonstrating a ca. 1.5 pH units change by a matrix synthesized using 100 electropolymerization cycles. The pH changes are used to reversibly activate and deactivate a C-quadruplex (i-motif)-bridged Mg(2+)-dependent DNAzyme.
authors.affiliation: Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Marco
authors.initials: M
authors.lastname: Frasconi
authors.forename: Ran
authors.initials: R
authors.lastname: Tel-Vered
authors.forename: Johann
authors.initials: J
authors.lastname: Elbaz
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D001483:Base Sequence; D003432:Cross-Linking Reagents / Q000737:chemistry; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021881:DNA, Catalytic / Q000378:metabolism; D004563:Electrochemistry; D004566:Electrodes; D004789:Enzyme Activation; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D053761:Nanocomposites / Q000737:chemistry*; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D003432:Cross-Linking Reagents; D021881:DNA, Catalytic; D011108:Polymers; D006046:Gold; D004247:DNA; C023650:aniline