title: On-chip detection of rolling circle amplified DNA molecules from Bacillus globigii spores and Vibrio cholerae.
abstract: For the first time DNA coils formed by rolling circle amplification are quantified on-chip by Brownian relaxation measurements on magnetic nanobeads using a magnetoresistive sensor. No external magnetic fields are required besides the magnetic field arising from the current through the sensor, which makes the setup very compact. Limits of detection down to 500 Bacillus globigii spores and 2 pM of Vibrio cholerae are demonstrated, which are on the same order of magnitude or lower than those achieved previously using a commercial macro-scale AC susceptometer. The chip-based readout is an important step towards the realization of field tests based on rolling circle amplification molecular analyses.
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800, Kongens Lyngby, Denmark.
authors.forename: Frederik W
authors.initials: FW
authors.lastname: Østerberg
authors.forename: Giovanni
authors.initials: G
authors.lastname: Rizzi
authors.forename: Marco
authors.initials: M
authors.lastname: Donolato
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Bejhed
authors.forename: Anja
authors.initials: A
authors.lastname: Mezger
authors.forename: Mattias
authors.initials: M
authors.lastname: Strömberg
authors.forename: Mats
authors.initials: M
authors.lastname: Nilsson
authors.forename: Maria
authors.initials: M
authors.lastname: Strømme
authors.forename: Peter
authors.initials: P
authors.lastname: Svedlindh
authors.forename: Mikkel F
authors.initials: MF
authors.lastname: Hansen
mesh_terms: D001407:Bacillus / Q000737:chemistry* / Q000235:genetics; D015374:Biosensing Techniques / Q000379:methods; D004269:DNA, Bacterial / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D004270:DNA, Circular / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D058185:Magnetite Nanoparticles; D046210:Microfluidic Analytical Techniques / Q000379:methods; D021141:Nucleic Acid Amplification Techniques; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D013171:Spores, Bacterial / Q000737:chemistry / Q000235:genetics; D014734:Vibrio cholerae / Q000737:chemistry* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular; D058185:Magnetite Nanoparticles
keywords: biosensors; brownian relaxation; lab-on-a-chip; magnetic field sensors; magnetic nanoparticles