Homogeneous differential magnetic assay
Journal article, 2019
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.
homogeneous differential magnetic assay
microfluidics
Brownian relaxation
magnetic nanoparticles
rolling circle amplification
Author
Sobhan Sepehri
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Teresa Zardán Gómez De La Torre
Uppsala University
Justin Schneiderman
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Jakob Blomgren
RISE Research Institutes of Sweden
Aldo Jesorka
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Christer Johansson
Chalmers, Microtechnology and Nanoscience (MC2)
Mats Nilsson
Science for Life Laboratory (SciLifeLab)
Jan Albert
Karolinska University Hospital
Karolinska Institutet
Maria Strømme
Uppsala University
Dag Winkler
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Alexei Kalaboukhov
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
ACS Sensors
23793694 (eISSN)
Vol. 4 9 2381-2388Point-of care Influenza Diagnostics FLU-ID
Swedish Foundation for Strategic Research (SSF) (SBE13-0125), 2021-01-01 -- 2021-03-31.
Swedish Foundation for Strategic Research (SSF) (SBE13-0125), 2014-06-01 -- 2020-12-31.
Areas of Advance
Nanoscience and Nanotechnology
Subject Categories
Analytical Chemistry
Medical Equipment Engineering
Other Physics Topics
Biomedical Laboratory Science/Technology
Nano Technology
Other Industrial Biotechnology
Driving Forces
Innovation and entrepreneurship
Infrastructure
Nanofabrication Laboratory
DOI
10.1021/acssensors.9b00969