Magnetic-Particle-Sensing Based Diagnostic Protocols  and Applications

Takamura, Tsukasa; Ko, Pil Ju; Sharma, Jaiyam; Yukino, Ryoji; Ishizawa, Shunji; Sandhu, Adarsh

doi:10.3390/s150612983

Cited by 19 publications

(9 citation statements)

References 16 publications

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“…The "real" signal is calculated by including bead interactions and the effects related to bead position with respect to the device active area, following the complete modeling procedure described in Section II. The second one is obtained by approximating the magnetic field observed by the k-th bead, namely B k in (7), as B dc . In this way, we exclude the magnetostatic interactions between beads, but we take into account the relevant information about the location of bead array.…”

Section: B Influence Of Bead Numbermentioning

confidence: 99%

“…Additionally, they are generally characterized by a linear response, being not affected by magnetic saturation as magnetoresistive devices. These features make miniaturized Hall sensors suitable for the detection of magnetic nanobeads [4][5][6][7][8][9] used as labels for manipulating, monitoring and Manuscript received October 03, 2018. This work was supported by Project 15SIB06 NanoMag "Nano-scale traceable magnetic field measurements", a joint research project funded by the European Metrology Programme for Innovation and Research (EMPIR).…”

Section: Introductionmentioning

confidence: 99%

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Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

2018

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This paper investigates the suitability of miniaturized semiconductor Hall devices for the quantification of magnetic nanobeads usable in biomedical applications. The analysis demonstrates the existence of conditions for which the Hall voltage signal is not proportional to bead number, focusing on the detection of a 2D array of superparamagnetic nanobeads, immobilized on the sensor surface. The study is performed by means of a numerical modeling procedure, which provides the spatial distribution of the electric potential inside the Hall plate, under the assumptions of diffusive electron transport regime and non-uniform magnetic field. We find that proportionality of the sensor response to bead number and possibility to use micro-Hall devices as magnetic bead counters are strongly affected by the magnetostatic dipolar interactions between beads. We also observe a deviation from linearity, due to the spatial nonuniformity in the device response, which is strongly influenced by the planar position of the beads with respect to the device active area. These aspects are investigated in detail by varying external field amplitude, device dimension, bead number, interbead distance, bead vertical position and size of the area occupied by beads. The parametric analysis is performed simulating an ac-dc Hall magnetometry technique.

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Section: B Influence Of Bead Numbermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

2018

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“…The magnetic stray field of the beads changes the resistance of the gel through the granular GMR effect, enabling the detection and quantification of the bound beads [ 26 ]. In a review on magnetic particle sensing, Takamura et al report on an approach for the detection of sub-200 nm magnetic particles via columnar particle arrangements [ 27 ]. Llandro et al describe the physical concepts of various sensor types used to detect magnetic labels in the application field of magnetic biosensors [ 28 ].…”

Section: Magnetic Bead Properties and Synthesismentioning

confidence: 99%

“…It should be mentioned, that the use of magnetic bead columnar arrangements or chains is not only restricted to mixing: Raman et al used the chaining effect for the determination of the orientation in copolymer nanodomains through the alignment and chaining of superparamagnetic nanoparticles in a magnetic field [ 44 ]. Dreyfus et al accomplished the measurement of colloidal forces with the magnetic chaining technique [ 45 ], while Takamura et al accomplish magnetic particle detection based on magnetic bead chains in rotating magnetic fields [ 27 ].…”

Section: Magnetic Bead Applicationsmentioning

confidence: 99%

Magnetic Bead—Magic Bullet

Ruffert¹

2016

Micromachines

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Microfluidics is assumed to be one of the leading and most promising areas of research since the early 1990s. In microfluidic systems, small spherical magnetic particles with superparamagnetic properties, called magnetic beads, play an important role in the design of innovative methods and tools, especially in bioanalysis and medical sciences. The intention of this review paper is to address main aspects from the state-of-the-art in the area of magnetic bead research, while demonstrating the broad variety of applications and the huge potential to solve fundamental biological and medical problems in the fields of diagnostics and therapy. Basic issues and demands related to the fabrication of magnetic particles and physical properties of nanosize magnets are discussed in Section 2. Of main interest are the control and adjustment of the nanoparticles’ properties and the availability of adequate approaches for particle detection via their magnetic field. Section 3 presents an overview of magnetic bead applications in nanomedicine. In Section 4, practical aspects of sample manipulation and separation employing magnetic beads are described. Finally, the benefits related to the use of magnetic bead-based microfluidic systems are summarized, illustrating ongoing questions and open tasks to be solved on the way to an approaching microfluidic age.

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“…Digital lock-in amplifiers (DLIAs) have been widely used for measuring weak signals in numerous fields [1], such as Raman spectroscopy [2], atomic force microscopy [3,4], multifunctional scanning tunneling microscopy [5], and sensors and actuators [6,7]. The measurement principle of LIAs [8] carries out a correlative demodulation with the same reference frequency as the carrier signal to single out the component of the signal at a specific reference frequency and phase.…”

Section: Introductionmentioning

confidence: 99%

A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement

Huang

Geng

Zhang

et al. 2019

Sensors

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In this work, we report on the design of a wide-band digital lock-in amplifier (DLIA) of up to 65 MHz and its application for electrical impedance measurements in microfluidic devices. The DLIA is comprised of several dedicated technologies. First, it features a fully differential analog circuit, which includes a preamplifier with a low input noise of 4.4 nV/√Hz, a programmable-gain amplifier with a gain of 52 dB, and an anti-aliasing, fully differential low-pass filter with −76 dB stop-band attenuation. Second, the DLIA has an all-digital phase lock loop, which features a phase deviation of less than 0.02° throughout the frequency range. The phase lock loop utilizes an equally accurate period-frequency measurement, with a sub-ppm precision of frequency detection. Third, a modified clock link is implemented in the DLIA to improve the signal-to-noise ratio of the analog-to-digital converter affected by clock jitter of up to 20 dBc. A series of measurements were performed to characterize the DLIA, and the results showed an accurate performance. Additionally, impedance measurements of standard-size microparticles were performed by frequency sweep from 300 kHz to 30 MHz, using the DLIA in a microfluidic device. Different diameters of microparticle could be accurately distinguished according to the relative impedance at 2.5 MHz. The results confirm the promising applications of the DLIA in microfluidic electrical impedance measurements.

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Magnetic-Particle-Sensing Based Diagnostic Protocols and Applications

Cited by 19 publications

References 16 publications

Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

Quantification of Magnetic Nanobeads With Micrometer Hall Sensors

Magnetic Bead—Magic Bullet

A Wide-Band Digital Lock-In Amplifier and Its Application in Microfluidic Impedance Measurement

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