Magnetic relaxation measurement in immunoassay using high-transition-temperature superconducting quantum interference device system

Abstract

Articles you may be interested inBiofunctionalized magnetic nanoparticles for high-sensitivity immunomagnetic detection of human C-reactive protein Appl. Phys. Lett. 88, 252506 (2006); 10.1063/1.2207990 Brownian magnetic relaxation of water-based cobalt nanoparticle ferrofluids J. Appl. Phys. 99, 08H107 (2006); 10.1063/1.2172203 Investigation of superparamagnetic Fe 3 O 4 nanoparticles by fluxgate magnetorelaxometry for use in magnetic relaxation immunoassaysSuperconducting quantum interference device-based magnetic nanoparticle relaxation measurement as a novel tool for the binding specific detection of biological binding reactions (abstract) Due to their ultrahigh sensitivity to magnetic flux, superconducting quantum interference devices ͑SQUIDs͒ are able to detect biomagnetic signals. By labeling biotargets with magnetic nanoparticles, several groups have shown that SQUIDs are promising as quantitative probes of biotargets by measuring their magnetic properties. In this work, we describe the design and construction of a high-transition-temperature radio-frequency SQUID magnetometer system for measuring the magnetic relaxation of labeled avidin. We also describe the synthesis of magnetic nanoparticles coated with biotin for use in labeling the avidin. Furthermore, the specifications of the SQUID-based magnetically labeled immunoassay of avidin are explored.

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

“…The magnetic nanoparticles are Fe 3 O 4 with dextran as outmost layer (MagQu Co. Ltd.). Anti-Hb and anti-HbA1c were covalently bound with dextran [6]. The magnetic nanoparticles have a mean diameter of 67 nm.…”

“…By bio-functionalizing the surface of magnetic nanoparticles with antibodies, magnetic nanoparticles become useful in diagnosis such as magnetic resonance imaging (MRI) contrast agent [1,2], molecule extraction, or immunoassay [3][4][5][6]. Especially in immunoassay, numerous reports show advantages and promising clinical applications when using bio-functionalized magnetic nanoparticles as labeling markers.…”

A new approach for bioassays based on frequency- and time-domain measurements of magnetic nanoparticles

“…Several groups, of which we are one, have demonstrated the feasibility of using biomolecular-mediated clustering of MNP systems in the context of bioassay measurements (Astalan et al, 2007;Oisjoen et al, 2009b;Yang et al, 2006). Other protocols are based on biospecific binding to the walls of a well (Enpuku et al, 2001), to agarose beads (Eberbeck et al, 2008), or large yeast cells (Eberbeck et al, 2005) in order to immobilize the MNPs.…”

“…In recent years, several groups have developed new bioassay methodologies that employ detection of biofunctional MNPs with readout based on induction coils (Astalan et al, 2004(Astalan et al, , 2006(Astalan et al, , 2007, frequency mixing (Krause et al, 2007;Nikitin et al, 2007;Yang et al, 2006) or a quartz crystal microbalance (QCM) (Lee et al, 2005;Liu et al, 2001;Yokoyama et al, 1995). The frequency mixing technique employs the nonlinear magnetic response of the MNPs at high fields to mix applied frequencies thereby separating the excitation from the readout signals and reducing the background signal contribution.…”

Dual immobilization and magnetic manipulation of magnetic nanoparticles

“…For example, by coating antibodies onto magnetic nanoparticles [1,2], magnetic nanoparticles serve as bio-markers for interested tissues or molecules. Magnetic-nanoparticle bio-markers are now popularly used in magnetic resonance imaging [3,4], immunoassay [5][6][7][8], DNA assay [9][10][11], and cell sorting. In addition to bio-markers, biofunctionalized magnetic nanoparticles can be vectors, which are useful in gene transfection and drug delivery [12,13].…”