Blu-ray optomagnetic measurement based competitive immunoassay for Salmonella detection
2016 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 77, 32-39 p.Article in journal (Refereed) Published
A turn-on competitive immunoassay using a low-cost Blu-ray optomagnetic setup and two differently sized magnetic particles (micron-sized particles acting as capture particles and nano-sized particles acting as detection particles) is here presented. For Salmonella detection, a limit of detection of 8 x 10(4) CFU/mL is achieved within a total assay time of 3 h. The combination of a competitive strategy and an optomagnetic setup not only enables a turn-on read-out format, but also results in a sensitivity limit about a factor of 20 times lower than of volumetric magnetic stray field detection device based immunoassays. The improvement of sensitivity is enabled by the formation of immuno-magnetic aggregates providing steric hindrance protecting the interior binding sites from interaction with the magnetic nanoparticle labels. The formation of immuno-magnetic aggregates is confirmed by fluorescence microscopy. The system exhibits no visible cross-reaction with other common pathogenic bacteria, even at concentrations as high as 10 CFU/mL. Furthermore, we present results when using the setup for a qualitative and homogeneous biplex immunoassay of Escherichia coli and Salmonella typhimurium.
Place, publisher, year, edition, pages
2016. Vol. 77, 32-39 p.
Biosensors; Immunoassays; Magnetic particles; Magneto-optics
Engineering and Technology
Research subject Engineering Science with specialization in Solid State Physics
IdentifiersURN: urn:nbn:se:uu:diva-264720DOI: 10.1016/j.bios.2015.08.070ISI: 000366766900006OAI: oai:DiVA.org:uu-264720DiVA: diva2:861185
FunderSwedish Research Council Formas, 221-2012-444