A magnetic nanobead-based bioassay provides sensitive detection of single- and biplex bacterial DNA using a portable AC susceptometer
2014 (English)In: Biotechnology Journal, ISSN 1860-6768, Vol. 9, no 1, 137-145 p.Article in journal (Refereed) Published
Bioassays relying on magnetic read-out using probe-tagged magnetic nanobeads are potential platforms for low-cost biodiagnostic devices for pathogen detection. For optimal assay performance it is crucial to apply an easy, efficient and robust bead-probe conjugation protocol. In this paper, sensitive (1.5 pM) singleplex detection of bacterial DNA sequences is demonstrated in a portable AC susceptometer by a magnetic nanobead-based bioassay principle; the volume-amplified magnetic nanobead detection assay (VAM-NDA). Two bead sizes, 100 and 250 nm, are investigated along with a highly efficient, rapid, robust, and stable conjugation chemistry relying on the avidin-biotin interaction for bead-probe attachment. Avidin-biotin conjugation gives easy control of the number of detection probes per bead; thus allowing for systematic investigation of the impact of varying the detection probe surface coverage upon bead immobilization in rolling circle amplified DNA-coils. The existence of an optimal surface coverage is discussed. Biplex VAM-NDA detection is for the first time demonstrated in the susceptometer: Semi-quantitative results are obtained and it is concluded that the concentration of DNA-coils in the incubation volume is of crucial importance for target quantification. The present findings bring the development of commercial biodiagnostic devices relying on the VAM-NDA further towards implementation in point-of-care and outpatient settings.
Place, publisher, year, edition, pages
2014. Vol. 9, no 1, 137-145 p.
Research subject Engineering Science with specialization in Nanotechnology and Functional Materials; Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-210682DOI: 10.1002/biot.201300348ISI: 000337540100014OAI: oai:DiVA.org:uu-210682DiVA: diva2:663992
FunderVinnova, 2012-00770Formas, 2011-1692 221-2012-444Carl Tryggers foundation , CTS 12:554Swedish Research Council, 2010-2580