Label-free separation of nanoscale particles by an ultrahigh gradient magnetic field in a microfluidic device

Zeng, Lin; Chen, Xi; Du, Jing; Yu, Zitong; Zhang, Rongrong; Zhang, Yi; Yang, Hui

doi:10.1039/d0nr08383f

Cited by 22 publications

(20 citation statements)

References 38 publications

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“…In the experiments, the optimal concentration of the ferrofluid was chosen as 0.003× (0.01%), based on our precious study [ 31 ]. Here, we first optimized the flow rate of the sample, the results of which are shown in Figure 4 .…”

Section: Resultsmentioning

confidence: 99%

“…In order to improve the size resolution, other forces such as viscoelasticity [ 27 ], inertial force [ 28 ], and centrifugal force [ 29 ] are combined with the negative magnetophoretic force in a single chip. Recently, new magnetic structures have been used to improve the magnetic field gradient, for example, utilizing four permanent magnets presented by Mao et al [ 30 ], as well as generating an on-chip magnetic pole array in our previously published work [ 31 ], both of which greatly improve the magnetic field gradient and successfully achieve a separation of 200 nm and 1000 nm particles, however the sample throughput in these two works is not high enough.…”

Section: Introductionmentioning

confidence: 99%

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High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System

et al. 2022

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The separation and purification of a sample of interest is essential for subsequent detection and analysis procedures, but there is a lack of effective separation methods with which to purify nano-sized particles from the sample media. In this paper, a microfluidic system based on negative magnetophoresis is presented for the high-resolution separation of nanoparticles. The system includes on-chip magnetic pole arrays and permalloys that symmetrically distribute on both sides of the separation channel and four permanent magnets that provide strong magnetic fields. The microfluidic system can separate 200 nm particles with a high purity from the mixture (1000 nm and 200 nm particles) due to a magnetic field gradient as high as 10,000 T/m being generated inside the separation channel, which can provide a negative magnetophoretic force of up to 10 pN to the 1000 nm particle. The overall recovery rate of the particles reaches 99%, the recovery rate of 200 nm particles is 84.2%, and the purity reaches 98.2%. Compared with the existing negative magnetophoretic separation methods, our system not only exhibits high resolution on particle sizes (800 nm), but also improves the sample processing throughput, which reaches 2.5 μL/min. The microfluidic system is expected to provide a new solution for the high-purity separation of nanoparticles, as well as nanobiological samples.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System

et al. 2022

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“…When magnetic agents are placed in the gradient fields, they will be forced to move by the magnetic force. The gradient fields have been used to separate the microparticles of 0.2 μm and 1 μm in sizes in fluids [26]. The particles of 0.2 μm represented by green fluorescence moved to lower outlets of a microchannel, while the larger particles (1 μm) labeled by red color were mainly concentrated at the upper outlets (Fig.…”

Section: Gradient Fieldsmentioning

confidence: 99%

Magnetic Microrobotic Swarms in Fluid Suspensions

Chen

2022

Curr Robot Rep

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Purpose of Review Microrobotic swarms have attracted extensive attentions due to their potential in medical and bioengineering applications. Because of the small sizes of swarm agents, integrating actuators, sensors, and control circuits are difficult. Microrobotic swarms in different fluid environments should be actuated and navigated by external physical fields, chemical fuels, and biological power. Magnetic fields have advantages, including real-time control, programmability, and high penetrability, and thus they are widely used to actuate magnetic microrobotic swarms. This review summarizes the recent remarkable progress in the magnetic actuation and navigation of magnetic microrobotic swarms. Recent Findings After development and evolution, the design of magnetic agents, and techniques of magnetic actuation and automatic control are now in place. Magnetic microrobotic swarms formed by different agents have been proposed, such as nanoparticles, artificial bacterial flagella, and bacteria. By tuning the applied fields, the morphology, orientation, and position of swarms can be adjusted on demand. Reconfigurability and motion dexterity are endowed to the microrobotic swarms. Summary The wireless magnetic actuation systems for microrobotic swarms are introduced, and the characteristics of microrobotic swarms actuated by different customized magnetic fields are described, such as rotating, oscillating, and hybrid fields. The results show that the swarm intelligence has been enhanced. Finally, the current challenges and opportunities in this field are discussed. The developments in materials, actuation methods, control strategies, and imaging modalities will transform the magnetic microrobotic swarms from lab to practical clinic.

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“…Figure 4d shows the principle and optical graphs of cells individually visible on the traps, according to the antibody functionalization of the beads. [77]. The chip consists of two microchannels to fabricate magnetic pole arrays (filled with Fe 3 O 4 powder, at 3 µm from the ca.…”

Section: Magnetic Fluidsmentioning

confidence: 99%

Magnetic Polymers for Magnetophoretic Separation in Microfluidic Devices

et al. 2021

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Magnetophoresis offers many advantages for manipulating magnetic targets in microsystems. The integration of micro-flux concentrators and micro-magnets allows achieving large field gradients and therefore large reachable magnetic forces. However, the associated fabrication techniques are often complex and costly, and besides, they put specific constraints on the geometries. Magnetic composite polymers provide a promising alternative in terms of simplicity and fabrication costs, and they open new perspectives for the microstructuring, design, and integration of magnetic functions. In this review, we propose a state of the art of research works implementing magnetic polymers to trap or sort magnetic micro-beads or magnetically labeled cells in microfluidic devices.

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Label-free separation of nanoscale particles by an ultrahigh gradient magnetic field in a microfluidic device

Abstract: High-resolution separating of 1 μm and 200 nm particles was achieved in a microfluidic system based on negative magnetophoresis ultilizing ultra-high gradient magnetic field greater than 100 000 T m−1 and a ferrofluid with ultra-low concentration (0.01%).

Cited by 22 publications

References 38 publications

High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System

High-Resolution Separation of Nanoparticles Using a Negative Magnetophoretic Microfluidic System

Magnetic Microrobotic Swarms in Fluid Suspensions

Magnetic Polymers for Magnetophoretic Separation in Microfluidic Devices

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