High‐Throughput, Protein‐Targeted Biomolecular Detection Using Frequency‐Domain Faraday Rotation Spectroscopy

Abstract

A clinically relevant magneto-optical technique (fd-FRS, frequency-domain Faraday rotation spectroscopy) for characterizing proteins using antibody-functionalized magnetic nanoparticles (MNPs) is demonstrated. This technique distinguishes between the Faraday rotation of the solvent, iron oxide core, and functionalization layers of polyethylene glycol polymers (spacer) and model antibody-antigen complexes (anti-BSA/BSA, bovine serum albumin). A detection sensitivity of ≈10 pg mL and broad detection range of 10 pg mL ≲ c ≲ 100 µg mL are observed. Combining this technique with predictive analyte binding models quantifies (within an order of magnitude) the number of active binding sites on functionalized MNPs. Comparative enzyme-linked immunosorbent assay (ELISA) studies are conducted, reproducing the manufacturer advertised BSA ELISA detection limits from 1 ng mL ≲ c ≲ 500 ng mL . In addition to the increased sensitivity, broader detection range, and similar specificity, fd-FRS can be conducted in less than ≈30 min, compared to ≈4 h with ELISA. Thus, fd-FRS is shown to be a sensitive optical technique with potential to become an efficient diagnostic in the chemical and biomolecular sciences.

Morphology and Magnetic Structure of the Ferritin Core during Iron Loading and Release by Magnetooptical and NMR Methods

“…They allowed us to discuss the mineral phase of the ferritin core and the way its morphology changes during iron loading and its release. This information is crucial for better understanding of the etiology of neurodegenerative diseases, and it can be also very useful in emerging clinical application of magnetooptical methods. − Aside from the purely biomedical applications, the knowledge on the morphology of the core in various phases of its constitution should benefit in better control of procedures utilizing ferritins as nanoreactors for the synthesis of different novel materials.…”

Giant Faraday rotation in atomically thin semiconductors

“…The Faraday effect is crucial for numerous scientific and technological advancements in astronomy, biology, chemistry, physics, and materials science. For instance, it is used for investigating the magnetic domain structure in solids 1 , 2 , nuclear magnetic resonance in fluids via optical detection 3 , 4 , paramagnetic gas molecule detection 5 , determination of magnetic fields 6 and electron-density distribution in outer space and celestial objects 7 , probing spin coherence in cold atoms 8 , quantum spin fluctuation measurements 9 , biochemical and biomolecular detection 10 , stabilization of laser frequency 11 , optical current sensing 12 , optical Hall effect 13 , and optical isolators 14 .…”

Magneto-Optical Study Toward Discrimination of Iron Mineral in Human Tissues

“…* corresponding author; e-mail: koral@amu.edu.pl Magnetic circular dichroism (MCD) spectroscopy for discrimination between magnetite and maghemite nanoparticles were lately proposed by others [13]. Magnetooptical methods are employed in broad spectrum of application [14] in which recent achievements in field of biomedicine can be included [15][16][17][18]. Although application these methods to study of biological tissues have not been often explored presumably because Faraday rotation (FR) is relatively small in a region far from resonance.…”