Homogeneous Differential Magnetic AssayShow others and affiliations
2019 (English)In: ACS Sensors, E-ISSN 2379-3694, Vol. 4, no 9, p. 2381-8Article in journal (Refereed) Published
Abstract [en]
Assays are widely used for detection of various targets, including pathogens, drugs, and toxins. Homogeneous assays are promising for the realization of point-of-care diagnostics as they do not require separation, immobilization, or washing steps. For low concentrations of target molecules, the speed and sensitivity of homogeneous assays have hitherto been limited by slow binding kinetics, time-consuming amplification steps, and the presence of a high background signal. Here, we present a homogeneous differential magnetic assay that utilizes a differential magnetic readout that eliminates previous limitations of homogeneous assays. The assay uses a gradiometer sensor configuration combined with precise microfluidic sample handling. This enables simultaneous differential measurement of a positive test sample containing a synthesized Vibrio cholerae target and a negative control sample, which reduces the background signal and increases the readout speed. Very low concentrations of targets down to femtomolar levels are thus detectable without any additional amplification of the number of targets. Our homogeneous differential magnetic assay method opens new possibilities for rapid and highly sensitive diagnostics at the point of care.
Place, publisher, year, edition, pages
American Chemical Society , 2019. Vol. 4, no 9, p. 2381-8
Keywords [en]
binding kinetics, Brownian relaxation, homogeneous differential magnetic assay, magnetic nanoparticle, rolling circle amplification, volumetric detection, Amplification, Molecules, Nanoparticles, Brownian relaxations, Magnetic nano-particles, Rolling circle amplifications, Nanomagnetics
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-39981DOI: 10.1021/acssensors.9b00969OAI: oai:DiVA.org:ri-39981DiVA, id: diva2:1359555
Note
Funding details: Vetenskapsrådet, VR, 2015-03640; Funding details: Stiftelsen för Strategisk Forskning, SSF; Funding details: Stiftelsen för Strategisk Forskning, SSF, SBE13-0125; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding text 1: S.S., J.F.S, A.K., and D.W. conceived and designed the experiments. S.S. conducted the experiments and analyzed the data. T.Z.G.d.l.T. contributed with the biochemical processes. A.J. helped with the fabrication of the microfluidics. J.B. performed reference ac susceptibility measurements and contributed in the discussion of the initial results. C.J. contributed in the discussion of the results and analysis. S.S. and A.K. drafted the manuscript. All authors reviewed the manuscript and provided comments. This work was supported through the Swedish Foundation for Strategic Research (SSF) Grant “FLU-ID” No. SBE13-0125, the Swedish Research Council Grant 2015-03640, the Knut and Alice Wallenberg Foundation, and the Swedish Infrastructure for Micro- and Nanofabrication–Myfab. The authors declare the following competing financial interest(s): S.S., A.K., and D.W. are co-inventors of a patent filed on the subject of this work. The other authors declare no competing interests.
2019-10-092019-10-092024-03-05Bibliographically approved