title: 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-1and broad detection range of 10 pg mL-1≲ cBSA≲ 100 µg mL-1are 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-1≲ cBSA≲ 500 ng mL-1. 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.
authors.affiliation: Health Sciences and Technology (HST), Institute for Medical Engineering and Science (IMES), Massachusetts Institute of Technology and Harvard University, 77 Massachusetts Avenue 76-679, Cambridge, MA, 02139, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Murdock
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of Central Florida, P.O. Box, 162450, ENGR 1, Rm. 213, Orlando, FL, 32816, USA.
authors.forename: Shawn A
authors.initials: SA
authors.lastname: Putnam
authors.affiliation: Department of Materials Science and Engineering, Advanced Materials Processing and Analysis Center, (AMPAC), Nanoscience Technology Center (NSTC), University of Central Florida, P.O. Box 162455, ENGR 1, Rm. 207, Orlando, FL, 32816, USA.
authors.forename: Soumen
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Materials Science and Engineering, Advanced Materials Processing and Analysis Center, (AMPAC), Nanoscience Technology Center (NSTC), University of Central Florida, P.O. Box 162455, ENGR 1, Rm. 207, Orlando, FL, 32816, USA.
authors.forename: Ankur
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 229, Towne Building, 220 South 33rd Street, Philadelphia, PA, 19104, USA.
authors.forename: Elyse D Z
authors.initials: ED
authors.lastname: Chase
authors.affiliation: Department of Materials Science and Engineering, Advanced Materials Processing and Analysis Center, (AMPAC), Nanoscience Technology Center (NSTC), University of Central Florida, P.O. Box 162455, ENGR 1, Rm. 207, Orlando, FL, 32816, USA.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Seal
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry; D002417:Cattle; D057166:High-Throughput Screening Assays / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D015203:Reproducibility of Results; D012399:Rotation; D012710:Serum Albumin, Bovine / Q000032:analysis* / Q000737:chemistry; D013057:Spectrum Analysis
chemical_list: D000906:Antibodies; D058185:Magnetite Nanoparticles; D012710:Serum Albumin, Bovine
keywords: Brownian motion; Faraday effect; iron oxide nanoparticles; magnetic relaxation; magneto-optical characterization