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Gold Nanowire Based Electrical DNA Detection Using Rolling Circle Amplification
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Molecular tools.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
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2014 (English)In: ACS Nano, ISSN 1936-0851, Vol. 8, no 2, 1147-1153 p.Article in journal (Refereed) Published
Abstract [en]

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 T Omega to k Omega for silver and to Omega 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.

Place, publisher, year, edition, pages
2014. Vol. 8, no 2, 1147-1153 p.
Keyword [en]
gold nanoparticles, rolling circle amplification, nanoelectronics, gold conjugation, metal enhancement
National Category
Medical and Health Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Solid State Physics; Engineering Science with specialization in Materials Science
URN: urn:nbn:se:uu:diva-222202DOI: 10.1021/nn4058825ISI: 000332059200008OAI: oai:DiVA.org:uu-222202DiVA: diva2:711274
Available from: 2014-04-09 Created: 2014-04-08 Last updated: 2015-07-07Bibliographically approved
In thesis
1. Development of Electrical Readouts for Amplified Single Molecule Detection
Open this publication in new window or tab >>Development of Electrical Readouts for Amplified Single Molecule Detection
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Molecular diagnostics is a fast growing field with new technologies being developed constantly. There is a demand for more sophisticated molecular tools able to detect a multitude of molecules on a single molecule level with high specificity, able to distinguish them from other similar molecules. This becomes very important for infectious diagnostics with the increasing antibiotic resistant viruses and bacteria, in gene based diagnostics and for early detection and more targeted treatments of cancer. For increased sensitivity, simplicity, speed and user friendliness, novel readouts are emerging, taking advantage of new technologies being discovered in the field of nanotechnology. 

This thesis, based upon four papers, examines two novel electrical readouts for amplified single molecule detection. Target probing is based upon the highly specific amplification technique rolling circle amplification (RCA). RCA enables localized amplification resulting in a long single stranded DNA molecule containing tandem repeats of the probing sequence as product. Paper I demonstrates sensitive detection of bacterial genomic DNA using a magnetic nanoparticles-based substrate-free method where as few as 50 bacteria can be detected. Paper II illustrates a new sensor concept based on the formation of conducting molecular nanowires forming a low resistance circuit. The rolling circle products are stretched to bridge an electrode gap and upon metallization the resistance drops by several orders of magnitude, resulting in an extremely high signal to noise ratio. Paper III explores a novel metallization technique, demonstrating the efficient incorporation of boranephosphonate modified nucleotides during RCA.  In the presence of a silver ion solution, defined metal nanoparticles are formed along the DNA molecule with high spatial specificity. Paper IV demonstrates the ability to manipulate rolling circle products by dielectrophoresis. In the presence of a high AC electric field the rolling circle products stretch to bridge a 10 µm electrode gap.  

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 46 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1091
Rolling circle amplification, metallization, electrical DNA detection, magnetic nanoparticles, dielectrophoresis, boranephosphonate modified nucleotides, DNA elongation
National Category
Biochemistry and Molecular Biology
Research subject
urn:nbn:se:uu:diva-247945 (URN)978-91-554-9219-9 (ISBN)
Public defence
2015-05-22, B41, BMC, Husargatan 3, Uppsala, 13:15 (English)
Available from: 2015-04-28 Created: 2015-03-25 Last updated: 2015-07-07

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Russell, CamillaWelch, KenCai, YixiaoBrucas, RimantasNikolajeff, FredrikSvedlindh, PeterNilsson, Mats
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