High‐Throughput, Protein‐Targeted Biomolecular Detection Using Frequency‐Domain Faraday Rotation Spectroscopy. Issue 12 (16th January 2017)

• Record Type: Journal Article
• Authors: Murdock, Richard J.; Putnam, Shawn A.; Das, Soumen; Gupta, Ankur; Chase, Elyse D. Z.; Seal, Sudipta
• Is Part Of: Small. Volume 13:Issue 12(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-01-16
• Subjects: Brownian motion -- Faraday effect -- iron oxide nanoparticles -- magnetic relaxation -- magneto‐optical characterization; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201602862
• Languages: English
• ISSNs: 1613-6810

Abstract

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 −1 and broad detection range of 10 pg mL −1 ≲ cBSA ≲ 100 µ g mL −1 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 −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. Abstract : Analyte detection is critical to a broad range of technologies . An effective magneto‐optical technique based on the Faraday rotation principle is reported—with complementary enzyme‐linked immunosorbent assay studies—to quantify the binding of bovine serum albumin proteins to antibody‐functionalized magnetic nanoparticles. The diagnostic technique also opens new avenues for both controlling and quantifying the number of active binding sites.