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Magnetic nanobeads present during enzymatic amplification and labeling for a simplified DNA detection protocol based on AC susceptometry
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
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Number of Authors: 5
2015 (English)In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 5, no 12, 127139Article in journal (Refereed) Published
Abstract [en]

Magnetic biosensors are promising candidates for low-cost point-of-care biodiagnostic devices. For optimal efficiency it is crucial to minimize the time and complexity of the assay protocol including target recognition, amplification, labeling and read-out. In this work, possibilities for protocol simplifications for a DNA biodetection principle relying on hybridization of magnetic nanobeads to rolling circle amplification (RCA) products are investigated. The target DNA is recognized through a padlock ligation assay resulting in DNA circles serving as templates for the RCA process. It is found that beads can be present during amplification without noticeably interfering with the enzyme used for RCA (phi29 polymerase). As a result, the bead-coil hybridization can be performed immediately after amplification in a one-step manner at elevated temperature within a few minutes prior to read-out in an AC susceptometer setup, i.e. a combined protocol approach. Moreover, by recording the phase angle xi = arctan(chi ''/chi'), where chi and chi '' are the in-phase and out-of-phase components of the AC susceptibility, respectively, at one single frequency the total assay time for the optimized combined protocol would be no more than 1.5 hours, often a relevant time frame for diagnosis of cancer and infectious disease. Also, applying the phase angle method normalization of AC susceptibility data is not needed. These findings are useful for the development of point-of-care biodiagnostic devices relying on bead-coil binding and magnetic AC susceptometry.

Place, publisher, year, edition, pages
2015. Vol. 5, no 12, 127139
National Category
Nano Technology Materials Engineering Physical Sciences
URN: urn:nbn:se:su:diva-126397DOI: 10.1063/1.4939570ISI: 000367596300039OAI: diva2:901565
Available from: 2016-02-08 Created: 2016-02-01 Last updated: 2016-02-08Bibliographically approved

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Ahlford, Annika
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Department of Biochemistry and BiophysicsScience for Life Laboratory (SciLifeLab)
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