TY - JOUR
T1 - Characterization of magnetic markers for liquid-phase immunoassays using brownian relaxation
AU - Enpuku, Keiji
AU - Watanabe, Hideki
AU - Higuchi, Yuichi
AU - Yoshida, Takashi
AU - Kuma, Hiroyuki
AU - Hamasaki, Naotaka
AU - Mitsunaga, Masakazu
AU - Kanzaki, Hisao
AU - Kandori, Akihiko
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/2
Y1 - 2012/2
N2 - We characterized the magnetic markers used in biological immunoassays based on Brownian relaxation. Because the markers are composed of aggregated nanoparticles, i.e., magnetic nanoclusters, we first clarified their magnetic properties using AC susceptibility measurements, magnetization (M-H) curves, and magnetic relaxation properties. Analyzing the experimental results, we obtained the key parameters for the immunoassay, i.e., hydrodynamic diameter d h, magnetic moment m B, and anisotropy energy E B of the markers. Because these parameters were distributed in practical samples, we took their distribution into account in the analysis. Next, we showed the relationship between these parameters obtained from different samples. It was shown that mB increased approximately in proportion to d h. On the other hand, no clear correlation between m B and E B was obtained. These results were very different from those expected from single-domain nanoparticles and must be taken into account when magnetic markers are used in immunoassays based on Brownian relaxation.
AB - We characterized the magnetic markers used in biological immunoassays based on Brownian relaxation. Because the markers are composed of aggregated nanoparticles, i.e., magnetic nanoclusters, we first clarified their magnetic properties using AC susceptibility measurements, magnetization (M-H) curves, and magnetic relaxation properties. Analyzing the experimental results, we obtained the key parameters for the immunoassay, i.e., hydrodynamic diameter d h, magnetic moment m B, and anisotropy energy E B of the markers. Because these parameters were distributed in practical samples, we took their distribution into account in the analysis. Next, we showed the relationship between these parameters obtained from different samples. It was shown that mB increased approximately in proportion to d h. On the other hand, no clear correlation between m B and E B was obtained. These results were very different from those expected from single-domain nanoparticles and must be taken into account when magnetic markers are used in immunoassays based on Brownian relaxation.
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U2 - 10.1143/JJAP.51.023002
DO - 10.1143/JJAP.51.023002
M3 - Article
AN - SCOPUS:84857301453
VL - 51
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
SN - 0021-4922
IS - 2 PART 1
M1 - 023002
ER -