title: Coupling two different nucleic acid circuits in an enzyme-free amplifier.
abstract: DNA circuits have proven to be useful amplifiers for diagnostic applications, in part because of their modularity and programmability. In order to determine whether different circuits could be modularly stacked, we used a catalytic hairpin assembly (CHA) circuit to initiate a hybridization chain reaction (HCR) circuit. In response to an input nucleic acid sequence, the CHA reaction accumulates immobilized duplexes and HCR elongates these duplexes. With fluorescein as a reporter each of these processes yielded  10-fold signal amplification in a convenient 96-well format. The modular circuit connections also allowed the output reporter to be readily modified to a G-quadruplex-DNAzyme that yielded a fluorescent signal.
authors.affiliation: Center for Systems and Synthetic Biology, Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Jiang
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ellington
mesh_terms: D001710:Biotin / Q000737:chemistry; D021881:DNA, Catalytic / Q000737:chemistry*; D044708:DNA, Concatenated / Q000138:chemical synthesis; D005456:Fluorescent Dyes / Q000737:chemistry; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D055767:Immobilized Proteins / Q000737:chemistry; D055029:Inverted Repeat Sequences; D021141:Nucleic Acid Amplification Techniques; D009195:Peroxidase / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry
chemical_list: D021881:DNA, Catalytic; D044708:DNA, Concatenated; D005456:Fluorescent Dyes; D061925:Immobilized Nucleic Acids; D055767:Immobilized Proteins; D001710:Biotin; D006427:Hemin; D019809:Streptavidin; D009195:Peroxidase