Multiplex Detection of Magnetic Beads Using Offset Field Dependent Frequency Mixing Magnetic Detection

Sensors, vol. 21, pp. 5859

Abstract

Magnetic immunoassays employing Frequency Mixing Magnetic Detection (FMMD) have recently become increasingly popular for quantitative detection of various analytes. Simultaneous analysis of a sample for two or more targets is desirable in order to reduce the sample amount, save consumables, and save time. We show that different types of magnetic beads can be distinguished according to their frequency mixing response to a two-frequency magnetic excitation at different static magnetic offset fields. We recorded the offset field dependent FMMD response of two different particle types at frequencies f1 + n⋅f2, n = 1, 2, 3, 4 with f1 = 30.8 kHz and f2 = 63 Hz. Their signals were clearly distinguishable by the locations of the extremes and zeros of their responses. Binary mixtures of the two particle types were prepared with different mixing ratios. The mixture samples were analyzed by determining the best linear combination of the two pure constituents that best resembled the measured signals of the mixtures. Using a quadratic programming algorithm, the mixing ratios could be determined with an accuracy of greater than 14%. If each particle type is functionalized with a different antibody, multiplex detection of two different analytes becomes feasible.

Authors 5

1. Ali Mohammad Pourshahidi Aachen Faculty of Mathematics, Computer Science and Natural Sciences

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062 Aachen, Germany

   Institute of Biological Information Processing-Biolelectronics (IBI-3), Forschungszentrum Jülich, 52425 Jülich, Germany

2. Stefan Achtsnicht Aachen Institute of Nano- and Biotechnologies (INB)

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Institute of Biological Information Processing-Biolelectronics (IBI-3), Forschungszentrum Jülich, 52425 Jülich, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen University of Applied Sciences, 52428 Jülich, Germany

3. Mrinal Murali Nambipareechee

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Biological Information Processing-Biolelectronics (IBI-3), Forschungszentrum Jülich, 52425 Jülich, Germany

4. Andreas Offenhäusser Aachen Faculty of Mathematics, Computer Science and Natural Sciences

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062 Aachen, Germany

   Institute of Biological Information Processing-Biolelectronics (IBI-3), Forschungszentrum Jülich, 52425 Jülich, Germany

5. Hans‐Joachim Krause corresponding Aachen Institute of Nano- and Biotechnologies (INB)

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Institute of Biological Information Processing-Biolelectronics (IBI-3), Forschungszentrum Jülich, 52425 Jülich, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen University of Applied Sciences, 52428 Jülich, Germany