Yang C.-C.Yang S.-Y.Chieh J.-J.Horng H.-E.Hong C.-Y.Yang H.-C.Chen K.H.Shih B.Y.TA-FU CHENMING-JANG CHIU2020-11-032020-11-0320111948-7193https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865491507&doi=10.1021%2fcn200028j&partnerID=40&md5=1c18f7e4bbe969b1008d1e9bce6bc1ffhttps://scholars.lib.ntu.edu.tw/handle/123456789/519926Magnetic nanoparticles biofunctionalized with antibodies against β-amyloid-40 (Aβ-40) and Aβ-42, which are promising biomarkers related to Alzheimer's disease (AD), were synthesized. We characterized the size distribution, saturated magnetizations, and stability of the magnetic nanoparticles conjugated with anti-Aβ antibody. In combination with immunomagnetic reduction technology, it is demonstrated such biofunctionalized magnetic nanoparticles are able to label Aβs specifically. The ultralow-detection limits of assaying Aβs in vitro using the magnetic nanoparticles via immunomagnetic reduction are determined to a concentration of ~10 ppt (10 pg/mL). Further, immunomagnetic reduction signals of Aβ-40 and Aβ-42 in human plasma from normal samples and AD patients were analyzed, and the results showed a significant difference between these two groups. These results show the feasibility of using magnetic nanoparticles with Aβs as reagents for assaying low-concentration Aβs through immunomagnetic reduction, and also provide a promising new method for early diagnosis of Alzheimer's disease from human blood plasma. ? 2011 American Chemical Society.[SDGs]SDG3amyloid beta protein[1-40]; amyloid beta protein[1-42]; magnetic nanoparticle; water; amyloid beta protein; amyloid beta protein (1 42); amyloid beta protein[1-40]; amyloid beta-protein (1-42); antibody; biological marker; dyes, reagents, indicators, markers and buffers; nanoparticle; peptide fragment; Alzheimer disease; Article; blood analysis; controlled study; early diagnosis; human; immunoassay; immunological procedures; immunomagnetic reduction; in vitro study; limit of detection; magnetism; molecular stability; particle size; physical parameters; plasma; synthesis; algorithm; article; chemistry; enzyme linked immunosorbent assay; immunochemistry; immunology; magnetism; metabolism; nuclear magnetic resonance imaging; Algorithms; Alzheimer Disease; Amyloid beta-Peptides; Antibodies; Biological Markers; Enzyme-Linked Immunosorbent Assay; Humans; Immunochemistry; Indicators and Reagents; Magnetic Resonance Imaging; Magnetics; Nanoparticles; Particle Size; Peptide Fragmentsjournal article10.1021/cn200028j228601732-s2.0-84865491507