Development of Multisample Biological Immunoassay System Using HTS SQUID and Magnetic Nanoparticles

Tsukamoto, Akira; Saitoh, Kazuo; Suzuki, Daisuke; Sugita, Nami; Seki, Yusuke; Kandori, Akihiko; Tsukada, Keiji; Sugiura, Yoshinori; Hamaoka, Shigenori; Kuma, Hiroyuki; Hamasaki, Naotaka; Enpuku, Keiji

doi:10.1109/tasc.2005.849988

Cited by 47 publications

(27 citation statements)

References 10 publications

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“…1. An HTS SQUID gradiometer [7] cooled by liquid nitrogen was used. The SQUID and cryostat are magnetically shielded by a cylindrical magnetic shield.…”

Section: A Squid Systemmentioning

confidence: 99%

Development of a SQUID System Using Field Reversal for Rapidly Detecting Bacteria

Tsukamoto

Mizoguchi

Kandori

et al. 2009

IEEE Trans. Appl. Supercond.

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Pathogen identification usually requires growth of the pathogen by culture, which requires considerable time and manipulation by an experienced operator, leading to delays in diagnosis and treatment. We have investigated pathogen detection using a highly sensitive HTS-SQUID and magnetic markers and have developed a rapid and simple pathogen detection method. The magnetic markers, magnetic nanoparticles coated with detecting antibodies, bind to the target substance (antigen). The magnetic signal of the bound markers is measured with the highly sensitive SQUID. A remarkable feature of the magnetic assay is the disappearance of the magnetic signal from the unbound markers due to Brownian rotation. This makes it possible to detect the magnetic signal of the bound magnetic markers without removal of the unbound markers. In practice, however, the residual field around the SQUID generates an undesired magnetic signal from the unbound markers as a result of biased Brownian rotation. We developed a field reversal method-a measurement scheme-that eliminates the magnetic signal from the unbound markers. A difference signal is obtained by subtracting the magnetic signals measured by applying a magnetization field in two directions. The validity of this method was demonstrated experimentally using polymer beads as simulated bacteria. Its feasibility was demonstrated by the detection of Candida albicans, a pathogenic fungus. A magnetic signal of 3 m8 0 was detected from a sample containing 300 cells of Candida albicans. The detection limit was estimated from the system noise level of 0.5 m8 0 to be about one hundred cells of Candida albicans, indicating that this method has high sensitivity. These results show that magnetic assay using a highly sensitive SQUID can provide rapid and simple pathogen testing without culture.

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“…1. An HTS SQUID gradiometer [7] cooled by liquid nitrogen was used. The SQUID and cryostat are magnetically shielded by a cylindrical magnetic shield.…”

Section: A Squid Systemmentioning

confidence: 99%

Development of a SQUID System Using Field Reversal for Rapidly Detecting Bacteria

Tsukamoto

Mizoguchi

Kandori

et al. 2009

IEEE Trans. Appl. Supercond.

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“…After the measurement method is optimized, many samples can be measured in a short time under the same measurement conditions [16]. For such sequential measurement of many samples, a rotating sample holder is installed with the magnetometer [17,18]. In this study, we have developed a hybrid type HTS-SQUID magnetometer for application to the fundamental analysis of magnetic properties and for convenient quantitative analysis by improvement of the driving mechanism and the high resolution electric magnet, and optimization of the SQUID detection unit.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Type HTS-SQUID Magnetometer With Vibrating and Rotating Sample

Tsukada

Morita

Matsunaga

et al. 2016

IEEE Trans. Appl. Supercond.

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Highly sensitive measurement of the very weak magnetic characteristics of magnetic particles in solution or of a solution itself is required for applications such as biomedical examinations. In this study, higher sensitivity and additional performance with relaxation measurement and harmonic signal detection were achieved by improvement of the driving mechanism and high resolution electric magnet, and optimization of the superconducting quantum interference device (SQUID) detection unit. A servomotor was used for sample vibration and rotation with precise control and high speed. For detection of the M-H characteristics, the sample was vibrated under the magnetic field in the electromagnet. For measuring the relaxation of the magnetization, the sample was rotated. A first-order differential pickup coil with a normal conducting wire connected to the input coil of a high temperature superconductor (HTS)-SQUID was used to detect the magnetic signal from the sample. High resolution measurement of the magnetic moment in the order of 10 -11 A m 2 was achieved with this system configuration. An AC magnetic field with a DC bias could then be applied to the sample for detection of the harmonic signal. The magnetic relaxation signal from the sample was measured by another of the same type of differential detection coil equipped outside of the electric magnet by rotating instead of vibrating the sample. Magnetization curve for a lowconcentration of iron nanoparticles with superparamagnetic character in solution was successfully measured using the developed magnetometer, and the relaxation phenomenon was also characterized.  Index Terms-magnetic susceptibility, SQUID, magnetometer, magnetization, Brownian relaxation.

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“…In addition, the use of such nanoparticles in bio-immunoassay, magnetic nanoparticle imaging, and magnetic drug targeting has been studied owing to their promising results in these applications. The inherent magnetic properties of these particles can be determined by measuring their magnetic susceptibility [2][3][4], relaxation [5][6][7], and remanence [8,9]. Lately, some researchers have reported the development of sensitive measurement systems that are capable of measuring the magnetic relaxation and remanence of magnetic nanoparticles in solution [7,10,11].…”

Section: Introductionmentioning

confidence: 99%

Effect of diamagnetic contribution of water on harmonics distribution in a dilute solution of iron oxide nanoparticles measured using high-Tc SQUID magnetometer

Saari

Tsukamoto

Kusaka

et al. 2015

Journal of Magnetism and Magnetic Materials

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a b s t r a c tThe magnetization curve of iron oxide nanoparticles in low-concentration solutions was investigated by a highly sensitive high-T c superconducting quantum interference device (SQUID) magnetometer. The diamagnetic contribution of water that was used as the carrier liquid was observed in the measured magnetization curves in the high magnetic field region over 100 mT. The effect of the diamagnetic contribution of water on the generation of harmonics during the application of AC and DC magnetic fields was simulated on the basis of measured magnetization curves. Although the diamagnetic effect depends on concentration, a linear relation was observed between the detected harmonics and concentration in the simulated and measured results. The simulation results suggested that improvement could be expected in harmonics generation because of the diamagnetic effect when the iron concentration was lower than 72 μg/ml. The use of second harmonics with an appropriate bias of the DC magnetic field could be utilized for realization of a fast and highly sensitive detection of magnetic nanoparticles in a low-concentration solution.

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Development of Multisample Biological Immunoassay System Using HTS SQUID and Magnetic Nanoparticles

Cited by 47 publications

References 10 publications

Development of a SQUID System Using Field Reversal for Rapidly Detecting Bacteria

Development of a SQUID System Using Field Reversal for Rapidly Detecting Bacteria

Hybrid Type HTS-SQUID Magnetometer With Vibrating and Rotating Sample

Effect of diamagnetic contribution of water on harmonics distribution in a dilute solution of iron oxide nanoparticles measured using high-Tc SQUID magnetometer

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