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 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.

Particle Manipulation Inside a Grooved Microfluidic Channel

2009 ◽  
Author(s):  
Hsiu-hung Chen ◽  
Dayong Gao
Keyword(s):  
Rapid Prototyping ◽  
Microfluidic Device ◽  
Microfluidic Channel ◽  
Lab On A Chip ◽  
Cell Suspensions ◽  
Microfluidic Channels ◽  
Particle Manipulation ◽  
Post Processing ◽  
Processing Stage ◽  
Submicron Structures

The manipulation of particles and cells in micro-fluids, such as cell suspensions, is a fundamental task in Lab-on-a-Chip applications. According to their analysis purposes in either the pre- or post-processing stage, particles/cells flowing inside a microfluidic channel are handled by means of enriching, trapping, separating or sorting. In this study, we report the use of patterning flows produced by a series of grooved surfaces with different geometrical setups integrated into a microfluidic device, to continuously manipulate the flowing particles (5 to 20 μm in diameters) of comparable sizes to the depth of the channel in ways of: 1) concentrating, 2) focusing, and 3) potential separating. The device is fabricated using soft lithographic techniques and is composed of inlets, microfluidic channels, and outlets for loading, manipulating and retrieving cell suspensions, respectively. Such fabrication methods allow rapid prototyping of micron or submicron structures with multiple layers and replica molding on those fabricated features in a clear polymer. The particles are evenly distributed in the entrance of the microchannel and illustrate the enriching, focusing, or size-selective profiles after passing through the patterning grooves. We expect that the techniques of manipulating cell suspensions from this study can facilitate the development of cell-based devices on 1) the visualization of counting, 2) the visualization of sizing, and 3) the particle separating.

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.

Characterization and sorting of cells based on stiffness contrast in a microfluidic channel

RSC Advances ◽  
2016 ◽  
Vol 6 (78) ◽  
pp. 74704-74714 ◽  
Author(s):  
P. Sajeesh ◽  
A. Raj ◽  
M. Doble ◽  
A. K. Sen
Keyword(s):  
Microfluidic Device ◽  
Microfluidic Channel

This paper reports the characterization and sorting of cells based on stiffness contrast. A microfluidic device with focusing and spacing control for stiffness based sorting of cells is designed, fabricated and demonstrated.

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.

Separation of Magnetic Beads in a Microfluidic Device: Modeling and Experimentation

2011 ◽  
Author(s):  
Scott S. H. Tsai ◽  
Jason S. Wexler ◽  
Ian M. Griffiths ◽  
Howard A. Stone
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Microfluidic Device ◽  
Magnetic Beads ◽  
Microfluidic System ◽  
Device Modeling ◽  
Fluid Stream ◽  
Similar System ◽  
Flow Through ◽  
Paramagnetic Beads

We describe a microfluidic system that uses a magnetic field to deflect paramagnetic beads in the direction normal to the flow. Through modeling and experimentation, we study this system to separate beads by their magnetic properties and size. We also use a similar system to move the beads from one fluid stream to an adjacent miscible stream.

scholarly journals Preparation of optimized concanavalin A-conjugated Dynabeads® magnetic beads for CUT&Tag

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259846
Author(s):  
Yasuhiro Fujiwara ◽  
Yuji Tanno ◽  
Hiroki Sugishita ◽  
Yusuke Kishi ◽  
Yoshinori Makino ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Concanavalin A ◽  
Magnetic Particles ◽  
Magnetic Beads ◽  
Protein A ◽  
Con A ◽  
Established Method ◽  
Genomic Location ◽  
Tn5 Transposase ◽  
Selection Of

Epigenome research has employed various methods to identify the genomic location of proteins of interest, such as transcription factors and histone modifications. A recently established method called CUT&Tag uses a Protein-A Tn5 transposase fusion protein, which cuts the genome and inserts adapter sequences nearby the target protein. Throughout most of the CUT&Tag procedure, cells are held on concanavalin A (con A)-conjugated magnetic beads. Proper holding of cells would be decisive for the accessibility of Tn5 to the chromatin, and efficacy of the procedure of washing cells. However, BioMag®Plus ConA magnetic beads, used in the original CUT&Tag protocol, often exhibit poor suspendability and severe aggregation. Here, we compared the BioMag beads and Dynabeads® magnetic particles of which conjugation of con A was done by our hands, and examined the performance of these magnetic beads in CUT&Tag. Among tested, one of the Dynabeads, MyOne-T1, kept excessive suspendability in a buffer even after overnight incubation. Furthermore, the MyOne-T1 beads notably improved the sensitivity in CUT&Tag assay for H3K4me3. In conclusion, the arrangement and the selection of MyOne-T1 refine the suspendability of beads, which improves the association of chromatin with Tn5, which enhances the sensitivity in CUT&Tag assay.

Sign in / Sign up

Export Citation Format

Share Document