scholarly journals Continuous-Flow Separation of Magnetic Particles from Biofluids: How Does the Microdevice Geometry Determine the Separation Performance?

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3030 ◽  
Author(s):  
Cristina González Fernández ◽  
Jenifer Gómez Pastora ◽  
Arantza Basauri ◽  
Marcos Fallanza ◽  
Eugenio Bringas ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Rational Design ◽  
Magnetic Particles ◽  
Magnetic Beads ◽  
Permanent Magnets ◽  
System Throughput ◽  
Separation Performance ◽  
High Particle ◽  
Section Shape ◽  
Geometrical Features

The use of functionalized magnetic particles for the detection or separation of multiple chemicals and biomolecules from biofluids continues to attract significant attention. After their incubation with the targeted substances, the beads can be magnetically recovered to perform analysis or diagnostic tests. Particle recovery with permanent magnets in continuous-flow microdevices has gathered great attention in the last decade due to the multiple advantages of microfluidics. As such, great efforts have been made to determine the magnetic and fluidic conditions for achieving complete particle capture; however, less attention has been paid to the effect of the channel geometry on the system performance, although it is key for designing systems that simultaneously provide high particle recovery and flow rates. Herein, we address the optimization of Y-Y-shaped microchannels, where magnetic beads are separated from blood and collected into a buffer stream by applying an external magnetic field. The influence of several geometrical features (namely cross section shape, thickness, length, and volume) on both bead recovery and system throughput is studied. For that purpose, we employ an experimentally validated Computational Fluid Dynamics (CFD) numerical model that considers the dominant forces acting on the beads during separation. Our results indicate that rectangular, long devices display the best performance as they deliver high particle recovery and high throughput. Thus, this methodology could be applied to the rational design of lab-on-a-chip devices for any magnetically driven purification, enrichment or isolation.

Magnetophoresis ‘meets’ viscoelasticity: deterministic separation of magnetic particles in a modular microfluidic device

Lab on a Chip ◽  
2015 ◽  
Vol 15 (8) ◽  
pp. 1912-1922 ◽  
Author(s):  
Francesco Del Giudice ◽  
Hojjat Madadi ◽  
Massimiliano M. Villone ◽  
Gaetano D'Avino ◽  
Angela M. Cusano ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Magnetic Particles ◽  
Magnetic Beads ◽  
Microfluidic Channel

Deflection of magnetic beads in a microfluidic channel can be improved through viscoelastic focusing.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

scholarly journals Rational Design of High-Performance Continuous-Flow Microreactors Based on Gold Nanoclusters and Graphene for Catalysis

2018 ◽  
Vol 6 (11) ◽  
pp. 15425-15433 ◽  
Author(s):  
Yanbiao Liu ◽  
Xiang Liu ◽  
Shengnan Yang ◽  
Fang Li ◽  
Chensi Shen ◽  
...  
Keyword(s):  
Continuous Flow ◽  
High Performance ◽  
Rational Design ◽  
Gold Nanoclusters ◽  
Flow Microreactors

Microstructure Of Fe-Nd-B Alloys Tailored To Approach Theoretical Coercrvtty Limits

1999 ◽  
Vol 5 (S2) ◽  
pp. 26-27
Author(s):  
Kannan M. Krishnan ◽  
Er. Girt ◽  
E. C. Nelson ◽  
G. Thomas ◽  
Ferdinand Hofer
Keyword(s):  
Magnetic Particles ◽  
Permanent Magnets ◽  
Spontaneous Magnetization ◽  
Particle Interaction ◽  
Maximum Energy ◽  
Interacting Particles ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Oriented Samples ◽  
The Difference

Performance of permanent magnets for a variety of applications is often determined by the maximum energy product (BH)max. In order to obtain high (BH)max permanent magnetic materials have to have large coercivity. In theory the coercive field of ideally oriented, non-interacting, single domain, magnetic particles, assuming Kl is much bigger than K2, was shown to be He = 2K1/Ms - N Ms, where Kl and K2 are the magnetocrystalline anisotropy constants, Ms is the spontaneous magnetization and N is the demagnetization factor. For randomly oriented non-interacting particles the Stoner-Wohlfarth model predicts that the value of Hc decreases to about half. However, experimentally obtained values of the coercitive fields in permanent magnets are 3 to 10 and 2 times smaller for well oriented and randomly oriented samples, respectively. This discrepancy was attributed to inter-particle interaction and the microstructure of the permanent magnets. In order to understand the difference between the theoretically predicted and experimentally obtained results for He we prepared rapidly quenched, Nd-rich, NdxFe14B (2 < x < 150) ribbons.

The development of APE-PCR for the cloning of genomic insertion sites of DNA elements

Biologia ◽  
2013 ◽  
Vol 68 (4) ◽  
Author(s):  
Zhongjuan Xu ◽  
Yanli Li ◽  
Zhengwei Mao ◽  
Bin Yin
Keyword(s):  
Insertional Mutagenesis ◽  
Magnetic Particles ◽  
Magnetic Beads ◽  
Genetic Regulation ◽  
Insertion Site ◽  
Primer Extension ◽  
Successful Implementation ◽  
Nano Scale ◽  
Dna Elements ◽  
Insertion Sites

AbstractInsertional mutagenesis is a productive strategy for the exploration of genetic regulation of important biological and pathological processes, such as tumorigenesis. Successful implementation of this strategy depends heavily on an efficient approach to the identification of insertion sites present in the host genome. Here, we have introduced an easy and efficient protocol, called Adenosine-ended Primer Extension Polymerase Chain Reaction (APE-PCR), which represents several advantages, including the Addition technique we previously developed, primer extension approach coupled with biotin-streptavidin based purification, introduction of nano-scale magnetic particles, and digestion of DNA with a combination of enzymes. We have demonstrated that APE-PCR is able to amplify more and larger specific proviral insertion site (PIS)-derived fragments, with a lower non-specific background produced, fewer steps and less DNA samples required, flexibility in choice of restriction enzymes applied, at a lower cost. Replacement of regular magnetic beads with nano-scale ones in the protocol can further increase its power. Moreover, even with small amount of sample DNA, PISs can be recovered and analyzed. Thus, based on the results provided from this study, we believe that APE-PCR represents an efficient method in mapping of PISs and likely, the insertion sites of other types of DNA elements as well.

Modelling Immunomagnetic Cell Capture in CFD

2008 ◽  
Author(s):  
Tobias Baier ◽  
Swaty Mohanty ◽  
Klaus Stefan Drese ◽  
Federica Rampf ◽  
Jungtae Kim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Magnetic Particles ◽  
Magnetic Beads ◽  
Stokes Equations ◽  
Type Equation ◽  
Standard Technique ◽  
Binding Kinetics ◽  
Navier Stokes ◽  
Target Cells ◽  
Cell Capture

The separation of cells from a complex sample by immunomagnetic capture has become a standard technique in the last decade and has also obtained increased attention for microfluidic applications. We present a model that incorporates binding kinetics for the formation of cell-bead complexes, which can easily be integrated into a computational fluid dynamics (CFD) code. The model relies on the three equation types: Navier-Stokes equations governing the fluid dynamics, convection-diffusion equations for non-magnetic cells and a Nernst-Planck type equation governing the temporal evolution of cell-bead complex concentrations. The latter two equations are augmented by appropriate ‘reaction’ terms governing the binding kinetics which is formulated as a population rate balance between creation and annihilation of cell-bead complexes. First, the simulation results show, that by means of the developed approach appropriate parameter sets can be identified which allow for a continuous separation of tagged cells (cell/bead complexes) from non-magnetic particles such as non-target cells entering with the target cells. Moreover tagged cells can be, to a certain extend, separated from unbound beads. Second, the computed concentrations at the outlet show a drastic drop for higher cell/bead complexes beyond a certain number of beads per cell. We show that a critical number of beads per cells exists where the binding is considerably reduced or the reaction cascade ceases completely. This occurs when cell/bead complex have a similar magnetic mobility as the free magnetic beads. The presented CFD model has been applied to the simulation of a generic continuous cell separation system showing that the method facilitates the design of magnetophoretic systems.

Mobile magnetic particles as solid-supports for rapid surface-based bioanalysis in continuous flow

Lab on a Chip ◽  
2009 ◽  
Vol 9 (21) ◽  
pp. 3110 ◽  
Author(s):  
Sally A. Peyman ◽  
Alexander Iles ◽  
Nicole Pamme
Keyword(s):  
Continuous Flow ◽  
Magnetic Particles ◽  
Solid Supports

scholarly journals Additive Manufacturing of Anisotropic Sm-Fe-N Nylon Bonded Permanent Magnets

2021 ◽  
Author(s):  
Kinjal Gandha ◽  
Mariappan Paranthaman ◽  
Brian Sales ◽  
Haobo Wang ◽  
Adrian Dalagan ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Magnetic Particles ◽  
Permanent Magnets ◽  
Cost Effective ◽  
Maximum Energy ◽  
Maximum Energy Product ◽  
Polyamide 12 ◽  
Energy Technologies ◽  
Energy Product ◽  
Bonded Magnet

Fabricating a bonded magnet with a near-net shape in suitable thermoplastic polymer binders is of paramount importance in the development of cost-effective energy technologies. In this work, anisotropic Sm2Fe17N3 (Sm-Fe-N) bonded magnets are additively printed using Sm-Fe-N anisotropic magnetic particles in a polymeric binder polyamide-12 (PA12). The anisotropic bonded permanent magnets are fabricated by Big Area Additive Manufacturing followed by post-aligned in a magnetic field. Optimal post-alignment results in an enhanced remanence of ~ 0.68 T in PA12 reflected in a parallel-oriented (aligned) measured direction. The maximum energy product achieved for the additively printed anisotropic bonded magnet of Sm-Fe-N in PA12 polymer is 78.8 KJ m-3. Our results show advanced processing flexibility of additive manufacturing for the development of Sm-Fe-N bonded magnets in polymer media designed for applications with no critical rare earth magnets.

scholarly journals Evolutionary design of magnetic soft continuum robots

2021 ◽  
Vol 118 (21) ◽  
pp. e2021922118
Author(s):  
Liu Wang ◽  
Dongchang Zheng ◽  
Pablo Harker ◽  
Aman B. Patel ◽  
Chuan Fei Guo ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Magnetic Particles ◽  
Permanent Magnets ◽  
Complex Geometry ◽  
Nonuniform Distribution ◽  
Evolutionary Design ◽  
Efficient Design ◽  
Continuum Robots ◽  
End Effector ◽  
Design And Optimization

Worldwide cardiovascular diseases such as stroke and heart disease are the leading cause of mortality. While guidewire/catheter-based minimally invasive surgery is used to treat a variety of cardiovascular disorders, existing passive guidewires and catheters suffer from several limitations such as low steerability and vessel access through complex geometry of vasculatures and imaging-related accumulation of radiation to both patients and operating surgeons. To address these limitations, magnetic soft continuum robots (MSCRs) in the form of magnetic field–controllable elastomeric fibers have recently demonstrated enhanced steerability under remotely applied magnetic fields. While the steerability of an MSCR largely relies on its workspace—the set of attainable points by its end effector—existing MSCRs based on embedding permanent magnets or uniformly dispersing magnetic particles in polymer matrices still cannot give optimal workspaces. The design and optimization of MSCRs have been challenging because of the lack of efficient tools. Here, we report a systematic set of model-based evolutionary design, fabrication, and experimental validation of an MSCR with a counterintuitive nonuniform distribution of magnetic particles to achieve an unprecedented workspace. The proposed MSCR design is enabled by integrating a theoretical model and the genetic algorithm. The current work not only achieves the optimal workspace for MSCRs but also provides a powerful tool for the efficient design and optimization of future magnetic soft robots and actuators.

Sign in / Sign up

Export Citation Format

Share Document