Nanomagnetic Particles for SQUID-Based Magnetically Labeled Immunoassay

Abstract

With the increasing importance of SQUID-based magnetically labeled immunoassay, the study on the synthesis of controllable sizes of magnetic nanoparticles plays a role to promote the accuracy of the immunoassay. In this work, Fe 3 O 4 nano-particles coated with a suitable bio-probe (biotin) are synthesized through chemical co-precipitation process to probe the bio-target (avidin). Through the synthesis developed here, the particle hydrodynamic diameter can be adjusted from 30 to 90 nm, which provide candidates for probing various bio-targets in the future. The amount of the magnetically labeled avidin is then analyzed via measuring the saturated magnetization or the remanence of the sample by using a SQUID magnetometer.

Magnetic nanoparticles for high-sensitivity detection on nucleic acids via superconducting-quantum-interference-device-based immunomagnetic reduction assay

“…The details of these chemical reactions for binding biotin to dextran have been reported in Ref. [15]. Finally, through magnetic separation, the unbound probing single-strand DNAs were removed from the magnetic reagent, whose pH was around 7-8.…”

Specific detection of CD133-positive tumor cells with iron oxide nanoparticles labeling using noninvasive molecular magnetic resonance imaging

“…[32][33][34] Briefly, a ferrite solution containing ferrous sulfate heptahydrate (FeSO 4 ⋅7H 2 O) and ferric chloride hexahydrate (FeCl 3 ⋅6H 2 O) in a stoichiometric ratio of 1:2 was mixed with an equal volume of aqueous dextran. Dextran was served as a surfactant for Fe 3 O 4 particles distributed in water because of its nontoxicity, hydrophilicity, and high affinity for biological macromolecules.…”

Use of immunomagnetic reduction for C-reactive protein assay in clinical samples

“…It has been shown technically that the magnetically labeled immunoassay has the merits of high sensitivity, 6 versatile diagnostic methods, [6][7][8][9] convenient processes, 7,8 and high accuracy for detecting biomarkers, and could potentially be used in the clinical setting. In fact, magnetic particles have been used in cell sorting for the detection of human leukocyte antigen B27, 10 and it has been shown that the performance of magnetic cell sorting is much better than that of flow cytometry.…”