On-Chip Detection of Rolling Circle Amplified DNA Molecules from Bacillus Globigii Spores and Vibrio Cholerae

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2014-07, Vol.10 (14), p.2877-2882
• Main Authors: Østerberg, Frederik W., Rizzi, Giovanni, Donolato, Marco, Bejhed, Rebecca S., Mezger, Anja, Strömberg, Mattias, Nilsson, Mats, Strømme, Maria, Svedlindh, Peter, Hansen, Mikkel F.
• Format: Article
• Language: English
• Subjects: Amplification; Bacillus - chemistry; Bacillus - genetics; Bacillus globigii; Bacteria; Biosensing Techniques - methods; biosensors; brownian relaxation; Cholera; Coils; Deoxyribonucleic acid; DNA; DNA, Bacterial - analysis; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Circular - analysis; DNA, Circular - chemistry; DNA, Circular - genetics; Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Solid State Physics; lab-on-a-chip; magnetic field sensors; Magnetic fields; magnetic nanoparticles; Magnetite Nanoparticles; Microfluidic Analytical Techniques - methods; Nanotechnology; Nucleic Acid Amplification Techniques; Oligonucleotide Array Sequence Analysis - methods; Sensors; Spores; Spores, Bacterial - chemistry; Spores, Bacterial - genetics; Teknisk fysik med inriktning mot fasta tillståndets fysik; Teknisk fysik med inriktning mot nanoteknologi och funktionella material; Vibrio; Vibrio cholerae; Vibrio cholerae - chemistry; Vibrio cholerae - genetics
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.201303325

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. Self‐exciting magnetoresistive sensors and magnetic nanobeads are used for the on‐chip quantification of DNA coils formed from cholera or bacterial spores by rolling circle amplification with pM detection limit and a two order of magnitude dynamic range.