Experimental Study on Low-Detection Limit for Immunomagnetic Reduction Assays by Manipulating Reagent Entities

Yang, Shieh‐Yueh; Yang, Che; Horng, Herng Er; Shih, Bo-Yuan; Chieh, Jen Jie; Hong, Chin Yih; Yang, Hong-Chang

doi:10.1109/tnb.2013.2240009

Cited by 13 publications

(13 citation statements)

References 13 publications

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“…The plasma levels of tau measured in this study are higher (about twofold) than those in the previous studies using either conventional enzyme-linked immunosorbent assay (ELISA) or other ultra-sensitive technology such as the Simoa TM digital ELISA (Zetterberg et al, 2013). The reasons may include that IMR is more resistant to the interference from other components in the blood such as albumin or bilirubin; the preparation of our sample is quite straightforward avoiding loss of target protein during multi-step processing; also our tau antibody recognizes all isoforms of tau therefore achieve higher measures (Chiu et al, 2013; Yang et al, 2013). …”

Section: Discussionmentioning

confidence: 99%

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Plasma Tau Levels in Cognitively Normal Middle-Aged and Older Adults

Chiu

Fan

Chen

et al. 2017

Front. Aging Neurosci.

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Using an ultra-sensitive technique, an immunomagnetic reduction assay, the plasma tau level can be measured to a limit of quantification of pg/ml. In total 126 cognitively normal middle-aged and older adults (45–95 years old) were recruited. The plasma tau levels were significantly higher in the older group (aged 65–95 years) 18.14 ± 7.33 pg/ml than those in the middle-aged group (aged 45–64 years) 14.35 ± 6.49 pg/ml when controlled gender and ApoEε4 carrier status (F = 3.102, P = 0.029). The ApoEε4 carriers had higher plasma tau levels than the non-carriers when controlled age and gender (F = 6.149, P = 0.001). Men had higher plasma tau levels than their women counterparts when controlled ApoEε4 carrier status and gender (F = 6.149, P = 0.001). The plasma tau levels were found to be positively associated with their ages (r = 0.359, P < 0.001). Regression analysis showed that age explained approximately 13% of the variance in the plasma tau levels, and explained more than 10% of the variance in the volumes of the hippocampus and white matter hypodensity (R2 change 0.123~0.167, all P < 0.001), and explained less than 10% of the variance in the volume of the amygdala, and central part of the corpus callosum (R2 change 0.085~0.097, all P = 0.001). However, the plasma tau levels do not further explain any residual variance in the volume of brain structures. In conclusion, the effect of age on the plasma tau levels should always be considered in clinical applications of this surrogate biomarker to middle-aged and elderly subjects.

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Section: Discussionmentioning

confidence: 99%

“…A 60-μl aliquot of plasma was mixed with 60 μl of reagent at room temperature for determination of the tau protein concentration. The underlying mechanism and the technological details of the immunomagnetic reduction assay are described in our previous reports (Chiu et al, 2012; Yang et al, 2013). …”

Section: Methodsmentioning

confidence: 98%

Plasma Tau Levels in Cognitively Normal Middle-Aged and Older Adults

Chiu

Fan

Chen

et al. 2017

Front. Aging Neurosci.

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“…The magnetic reagents used in this study were composed of biocompatible magnetic Fe 3 O 4 nanoparticles with dextran shell (MagQu Co, Ltd). To synthesize BMNs, polyclonal goat anti-CRP (Sigma-Aldrich, St Louis, MO, USA) was covalently bound to the dextran shell of Fe 3 O 4 via −CH = N− [ 11 , 12 ]. BMN, which consisted of Fe 3 O 4 -antiCRP, was then dispersed in phosphate buffered saline (PBS) solution with a pH of 7.4.…”

Section: Methodsmentioning

confidence: 99%

Magnetic Clustering Effect during the Association of Biofunctionalized Magnetic Nanoparticles with Biomarkers

Chen

Liao

et al. 2015

PLoS ONE

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We report herein an investigation into dynamic magnetic clustering that occurs during immunoassays as biofunctionalized magnetic nanoparticles (BMNs) become associated with biotargets. We measure the dynamic effective relaxation time τ eff(t) and use scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to investigate the C-reactive protein (CRP) as it associates with the BMN Fe3O4-antiCRP to form the magnetic cluster Fe3O4-antiCRP-CRP. The results indicate that τ eff(t) increases with increasing association time. In addition, the ration Δτ eff/τ 0 as a function of CRP concentration follows a characteristic logistic function, which provides a basis for estimating the quantity of biomolecules with a detection sensitivity close to 0.1 ppm. After the association, SEM and TEM images show that CRP and Fe3O4-antiCRP conjugate to form Fe3O4-antiCRP-CRP clusters hundreds of nanometers in size. The SEM and TEM images provide direct evidence of the formation of magnetic clustering.

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“…Figure 1 shows a schematic of the clustering process involving BMNs and dextran-coated Fe 3 O 4 nanoparticles. The procedures used for synthesizing BMNs consisting of anticarcinoembryonic antigens (anti-CEAs) coated on dextran-coated Fe 3 O 4 nanoparticles (MF-DEX-0060, MagQu Corp., Taiwan) were similar to those used in a previous study for synthesizing dextran-coated Fe 3 O 4 nanoparticles coated with anti-goat C-reactive protein [ 22 ]. Dextran-coated Fe 3 O 4 nanoparticles was oxidized using NaIO 4 to create aldehyde groups (−CHO), and dextran reacted with the antibodies of anti-CEAs (10C-CR2014M5, Fitzgerald, MA, USA) through −CH = N- to covalently conjugate the antibodies of anti-CEAs.…”

Section: Methodsmentioning

confidence: 99%

Assaying Carcinoembryonic Antigens by Normalized Saturation Magnetization

et al. 2015

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Biofunctionalized magnetic nanoparticles (BMNs) that provide unique advantages have been extensively used to develop immunoassay methods. However, these developed magnetic methods have been used only for specific immunoassays and not in studies of magnetic characteristics of materials. In this study, a common vibration sample magnetometer (VSM) was used for the measurement of the hysteresis loop for different carcinoembryonic antigens (CEA) concentrations (ΦCEA) based on the synthesized BMNs with anti-CEA coating. Additionally, magnetic parameters such as magnetization (M), remanent magnetization (MR), saturation magnetization (MS), and normalized parameters (ΔMR/MR and ΔMS/MS) were studied. Here, ΔMR and ΔMs were defined as the difference between any ΦCEA and zero ΦCEA. The parameters M, ΔMR, and ΔMS increased with ΦCEA, and ΔMS showed the largest increase. Magnetic clusters produced by the conjugation of the BMNs to CEAs showed a ΔMS greater than that of BMNs. Furthermore, the relationship between ΔMS/MS and ΦCEA could be described by a characteristic logistic function, which was appropriate for assaying the amount of CEAs. This analytic ΔMS/MS and the BMNs used in general magnetic immunoassays can be used for upgrading the functions of the VSM and for studying the magnetic characteristics of materials.

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Experimental Study on Low-Detection Limit for Immunomagnetic Reduction Assays by Manipulating Reagent Entities

Cited by 13 publications

References 13 publications

Plasma Tau Levels in Cognitively Normal Middle-Aged and Older Adults

Plasma Tau Levels in Cognitively Normal Middle-Aged and Older Adults

Magnetic Clustering Effect during the Association of Biofunctionalized Magnetic Nanoparticles with Biomarkers

Assaying Carcinoembryonic Antigens by Normalized Saturation Magnetization

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