Sensitivity enhancement of magneto-optical Faraday effect immunoassay method based on biofunctionalized ?-Fe2O3@Au core-shell magneto- plasmonic nanoparticles for the blood detection of Alzheimer's disease

In this work, we conducted a proof-of-concept experiment based on biofunctionalized magneto-plasmonic nanoparticles (MPNs) and magneto-optical Faraday effect for in vitro Alzheimer's disease (AD) assay. The biofunctionalized gamma-Fe2O3@Au MPNs of which the surfaces are modified with the antibody of Tau protein (anti-tau). As anti-tau reacts with Tau protein, biofunctionalized MPNs aggregate to form magnetic clusters which will hence induce the change of the reagent's Faraday rotation angle. The result showed that the gamma-Fe2O3@Au core-shell MPNs can enhance the Faraday rotation with respect to the raw gamma-Fe2O3 nanoparticles. Because of their magneto-optical enhancement effect, biofunctionalized gamma-Fe2O3@Au MPNs effectively improve the detection sensitivity. The detection limit of Tau protein as low as 9 pg/mL (9 ppt) was achieved. Furthermore, the measurements of the clinical samples from AD patients agreed with the CDR evaluated by the neurologist. The results suggest that our method has the potential for disease assay applications. (cC) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, we conducted an experiment for in vitro Alzheimer's disease assay using biofunctionalized magneto-plasmonic nanoparticles and magneto-optical Faraday effect. The results showed that the biofunctionalized nanoparticles effectively enhanced the detection sensitivity and agreed with the clinical samples, suggesting their potential for disease assay applications.