title: Magnetic immunoassay platform based on the planar frequency mixing magnetic technique.
abstract: We represent the experimental results of our planar-frequency mixing magnetic detection (p-FMMD) technique to obtain 2D superparamagnetic images for magnetic immunoassay purpose. The imaging of magnetic beads is based on the nonlinear magnetic characteristics inherent in superparamagnetic materials. The p-FMMD records the sum-frequency components originating from both a high and a low frequency magnetic field incident on the magnetically nonlinear nanoparticles. In this study, we apply the p-FMMD technique to 2D scanning imaging of superparamagnetic iron oxide nanoparticles (SPIONs) in a microfluidic platform. Our p-FMMD system enables to acquire planar images of SPIONs filled in a microchannel as narrow as 30µm in width. The minimum detectable amount is ~1.0×10(8) beads of 100nm size. The system shows a spatial resolution enabling to distinguish between two distinct channels even 2mm apart from each other. Our p-FMMD system as a magnetic immunoassaying system has permitted the detection of amyloid beta 42 (Aβ42), a promising biomarker of Alzheimer's disease, at the minimum concentration of 23.8pg/ml. This may enable the identification of the Aβ42 levels for the early-stage of Alzheimer's disease with the assistance of the MPI using p-FMMD technique. The results show that the deployment of the p-FMMD can be an alternative to conventional biosensing analytical methods, and can be used as a fast and portable screening method.
authors.affiliation: IT Convergence Research Lab., Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Republic of Korea.
authors.forename: Chang-Beom
authors.initials: CB
authors.lastname: Kim
authors.affiliation: IT Convergence Research Lab., Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Republic of Korea.
authors.forename: Eul-Gyoon
authors.initials: EG
authors.lastname: Lim
authors.affiliation: IT Convergence Research Lab., Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Republic of Korea.
authors.forename: Sung Woong
authors.initials: SW
authors.lastname: Shin
authors.affiliation: Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich, 52425 Jülich, Germany. Electronic address: h.-j.krause@fz-juelich.de.
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Krause
authors.affiliation: IT Convergence Research Lab., Electronics and Telecommunications Research Institute (ETRI), Daejeon 34129, Republic of Korea. Electronic address: hb8868@etri.re.kr.
authors.forename: Hyobong
authors.initials: H
authors.lastname: Hong
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis; D016229:Amyloid beta-Peptides / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D056656:Lab-On-A-Chip Devices; D060526:Magnetic Fields; D008280:Magnetics / Q000295:instrumentation*; D058185:Magnetite Nanoparticles / Q000737:chemistry; D010446:Peptide Fragments / Q000032:analysis*
chemical_list: D016229:Amyloid beta-Peptides; D058185:Magnetite Nanoparticles; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)
keywords: 2D magnetic imaging; Biosensor; FMMD; Magnetic immunoassay; Magnetic nanoparticle; Superparamagnetism