Analysis of individual magnetic particle motion near a chip surface

Ommering, Kim van; Lamers, Carolien C. H.; Nieuwenhuis, Jeroen H.; IJzendoorn, L.J. van; Prins, Mwj Menno

doi:10.1063/1.3118500

Cited by 15 publications

(15 citation statements)

References 30 publications

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“…F m , calculated for an SPB with a radius of 1.4 lm and a susceptibility of 1.2 46 in a solution with a viscosity of 1 Â 10 À3 PaÁs, has a maximum value of 2.2 pN at the edges of the disk, which is sufficient to trap SPBs. 8,9,13,15,[20][21][22][26][27][28][29][30][31][32][33][34][35]47 Fig . 2(c) shows the velocity of an SPB during the trapping process.…”

Section: -4mentioning

confidence: 99%

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

et al. 2014

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This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.

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Section: -4mentioning

confidence: 99%

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

et al. 2014

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“…In current study, the immobilizing frequency was found to be 5.5 and 12.0 Hz for the 1.0 and 2.8 m diameter beads, respectively. Due to the magnetization differences in given lot of beads 15 , the beads shown different velocity of transport at low rotation frequencies. The threshold frequency introduced a minimum frequency for immobilizing majority of corresponding beads on micro-magnets array.…”

Section: Resultsmentioning

confidence: 99%

Flow-Enhanced Nonlinear Magnetophoresis for High-Resolution Bioseparation

Mahmood

2011

Langmuir

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A new mode of transport is described that was capable of high-resolution separation of superparamagnetic materials from complex mixtures based on their size. Laminar flow and a rotating external magnetic field were applied to superparamagnetic beads assembled on a semiperiodic micromagnet array. Beads at the edge of the micromagnet array oscillated in-phase with the external magnetic field with an amplitude that decreased with increasing frequency, ω, until they reached an immobilization frequency, ωi, where the beads stopped moving. Laminar flow along the edge of the array could be tuned to sweep the beads for which ω < ωi downstream at a velocity that increased with size while leaving beads for which ω > ωi undisturbed. Flow-enhanced nonlinear magnetophoresis (F-NLM) promises to enable multiple superparamagnetc bead types to be used in the fractionation of cells and implementation of diagnostic assays.

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“…However, the Brownian motion of the magnetic beads becomes more and more obvious with the increase of temperatures. To verify the influence of Brownian motion the following relation is applied (Ommering et al 2009):…”

Section: Effect Of Fluid Temperaturementioning

confidence: 99%

Enhancement of separation efficiency on continuous magnetophoresis by utilizing L/T-shaped microchannels

2011

Microfluid Nanofluid

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In this article a novel design of on-chip continuous magnetophoretic separator was proposed by utilizing the magnetic field and L-turning/T-junction effect of the flow field for high throughput applications. The motion of the magnetic bead was simulated based on Lagrangian tracking method and the separation efficiency was calculated according to the trajectories. Impact parameters including geometrical configuration, fluid velocity, magnetic flux density, magnetic bead size, and temperature on separation efficiency were discussed. The results show that both the L-and T-microchannel separators have higher separation efficiency as compared with the conventional straight-microchannel separator because of the L-turning/T-junction effect of the flow field. The separation efficiencies for L-and T-microchannel separators are 63.4 and 100%, respectively, while it is only 43.7% for straight-microchannel separator at the same conditions. Above a critical flow rate the separation efficiency drops drastically from nearly 100% to zero while this decrease is much slower for T-shaped configurations. The separation efficiency increases initially with the increase of the external magnetic flux density and keeps nearly constant at high magnetic flux density owing to saturated magnetization of the beads. It is also found that both the magnetic bead diameter and fluid temperature have great effect on the separation efficiency. The L/T-microchannel separators presented in this article are simple and efficient for magnetophoretic separation at high flow rates and thus useful for the high-efficiency on-chip enrichment of analytes with very low concentrations.

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Analysis of individual magnetic particle motion near a chip surface

Cited by 15 publications

References 30 publications

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

Flow-Enhanced Nonlinear Magnetophoresis for High-Resolution Bioseparation

Enhancement of separation efficiency on continuous magnetophoresis by utilizing L/T-shaped microchannels

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