title: Gold nanowire based electrical DNA detection using rolling circle amplification.
abstract: We present an electrical sensor that uses rolling circle amplification (RCA) of DNA to stretch across the gap between two electrodes, interact with metal nanoparticle seeds to generate an electrically conductive nanowire, and produce electrical signals upon detection of specific target DNA sequences. RCA is a highly specific molecular detection mechanism based on DNA probe circularization. With this technique, long single-stranded DNA with simple repetitive sequences are produced. Here we show that stretched RCA products can be metalized using silver or gold solutions to form metal wires. Upon metallization, the resistance drops from TΩ to kΩ for silver and to Ω for gold. Metallization is seeded by gold nanoparticles aligned along the single-stranded DNA product through hybridization of functionalized oligonucleotides. We show that combining RCA with electrical DNA detection produces results in readout with very high signal-to-noise ratio, an essential feature for sensitive and specific detection assays. Finally, we demonstrate detection of 10 ng of Escherichia coli genomic DNA using the sensor concept.
authors.affiliation: Department of Immunology, Genetics and Pathology, Uppsala University , SE-751 85 Uppsala, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Russell
authors.forename: Ken
authors.initials: K
authors.lastname: Welch
authors.forename: Jonas
authors.initials: J
authors.lastname: Jarvius
authors.forename: Yixiao
authors.initials: Y
authors.lastname: Cai
authors.forename: Rimantas
authors.initials: R
authors.lastname: Brucas
authors.forename: Fredrik
authors.initials: F
authors.lastname: Nikolajeff
authors.forename: Peter
authors.initials: P
authors.lastname: Svedlindh
authors.forename: Mats
authors.initials: M
authors.lastname: Nilsson
mesh_terms: D004247:DNA / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D053770:Nanowires
chemical_list: D006046:Gold; D004247:DNA