On-chip manipulation and trapping of microorganisms using a patterned magnetic pathway

Reddy, Venu; Lim, Byunghwa; Hu, Xinghao; Jeong, Il-Gyo; Ramulu, T.S.; Kim, C. G.

doi:10.1007/s10404-012-1046-z

Cited by 25 publications

(19 citation statements)

References 20 publications

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“…In this work, we used the monitoring setup which was reported earlier [13]. Briefly, the microfluidic chip was placed at the centre between two Helmholtz coil systems for the generation of a uniform magnetic field.…”

Section: Measurement Setupmentioning

confidence: 99%

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Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor

Kim¹,

Reddy²,

Kim³

et al. 2014

Journal of Magnetics

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In this study, we fabricate an integrated microfluidic chip with a planar Hall effect (PHE) sensor for single magnetic bead detection. The PHE sensor was constructed with a junction size of 10 µm × 10 µm using a trilayer structure of Ta(3 nm)/NiFe(10 nm)/Cu(1.2 nm)/IrMn(10 nm)/Ta(3 nm). The sensitivity of the PHE sensor was 19.86 µV/Oe. A diameter of 8.18 µm magnetic beads was used, of which the saturation magnetization was ~2.1 emu/g. The magnetic susceptibility χ of these magnetic beads was calculated to bẽ 0.14. The diluted magnetic beads solution was introduced to the microfluidic channel attributing a single bead flow and simultaneously the PHE sensor voltage was measured to be 0.35 µV. The integrated microchip was able to detect a magnetic moment of 1.98 × 10 −10 emu.

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Section: Measurement Setupmentioning

confidence: 99%

“…The microfluidic channels were prepared using a soft lithography procedure [13]. Briefly, a master for the channel a master with a width of 50 μm and thickness of 15 μm was prepared on a silicon wafer with SU-8 50 PR by using a negative pattern film mask.…”

Section: Introductionmentioning

confidence: 99%

Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor

Kim¹,

Reddy²,

Kim³

et al. 2014

Journal of Magnetics

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“…Several techniques have been developed to control bead motion, based on optical tweezers, [1][2][3] electromagnetic tweezers, 4,5 dielectrophoresis, 6,7 acoustic traps, 8,9 and on-chip micromagnets. [10][11][12][13][14][15] In particular, the ability to control large numbers of beads in parallel, by employing an external field and magnetizable features patterned in substrates, shows high potential for remotely organizing single particles and cells on on-chip.…”

Section: Introductionmentioning

confidence: 99%

“…This approach has been studied previously in colloidal suspensions interacting with arrays of optical traps, 16,17 or in periodic magnetization patterns exposed to a time-varying magnetic field. [10][11][12]14,[18][19][20][21][22] Magnetic separation, in particular, has notable advantages including its biocompatibility, absence of magnetic shielding from the environment, the wide selection of commercially available magnetic beads, and finally its ability to apply strong forces remotely to colloidal particles without significant heating or other deleterious effects.…”

Section: Introductionmentioning

confidence: 99%

Dynamic trajectory analysis of superparamagnetic beads driven by on-chip micromagnets

Abedini-Nassab

Lim

et al. 2015

Journal of Applied Physics

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We investigate the non-linear dynamics of superparamagnetic beads moving around the periphery of patterned magnetic disks in the presence of an in-plane rotating magnetic field. Three different dynamical regimes are observed in experiments, including (1) phase-locked motion at low driving frequencies, (2) phase-slipping motion above the first critical frequency f c1 , and (3) phase-insulated motion above the second critical frequency f c2 . Experiments with Janus particles were used to confirm that the beads move by sliding rather than rolling. The rest of the experiments were conducted on spherical, isotropic magnetic beads, in which automated particle position tracking algorithms were used to analyze the bead dynamics. Experimental results in the phase-locked and phaseslipping regimes correlate well with numerical simulations. Additional assumptions are required to predict the onset of the phase-insulated regime, in which the beads are trapped in closed orbits; however, the origin of the phase-insulated state appears to result from local magnetization defects. These results indicate that these three dynamical states are universal properties of bead motion in non-uniform oscillators. V C 2015 AIP Publishing LLC. [http://dx

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“…The desired capabilities of single-cell arrays bear strong resemblance to random access memory (RAM) computer chips, including the ability to introduce and retrieve single cells from precise locations of the chip (writing data), and query the biological state of specified cells at future time points (reading data). Existing particle handling tools based on hydrodynamic [8][9][10][11] , optic [12][13][14][15][16][17][18] , electric [19][20][21][22] and magnetic [23][24][25][26][27][28][29][30][31][32][33][34][35][36] trapping forces can achieve parts of this desired functionality; however, no single technique to our knowledge encompasses the scalability, flexibility and automation that allows single-cell chips to perform with the level of integration of computer circuits.…”

mentioning

confidence: 99%

Magnetophoretic circuits for digital control of single particles and cells

et al. 2014

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The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects. O ne of the main goals of lab-on-a-chip research is to develop generic platforms for manipulating small fluid droplets, colloidal particles and single cells with the flexibility, scalability and automation of modern-day computer circuits. Single-cell arrays represent one high impact application of lab-on-a-chip tools, which are increasingly being adopted to evaluate rare biological responses in small-cell subsets that are overlooked by the ensemble averaging approaches of traditional biology. Improved understanding of these rare cellular responses can profoundly impact the development of vaccines and pharmaceuticals for curing infectious diseases and cancer 1,2 ; however there are few existing techniques with the scale and flexibility to unmask single-cell heterogeneity and pave the way for new medical breakthroughs 3-7 .In particular, there is an urgent need for tools to organize large arrays of single cells and single-cell pairs, evaluate the temporal responses of individual cell and cell-pair interactions over long durations, and retrieve specific cells from the array for follow-on analyses. The desired capabilities of single-cell arrays bear strong resemblance to random access memory (RAM) computer chips, including the ability to introduce and retrieve single cells from precise locations of the chip (writing data), and query the biological state of specified cells at future time points (reading data). Existing particle handling tools based on hydrodynamic 8-11 , optic 12-18 , electric [19][20][21][22] and magnetic [23][24][25][26][27][28][29][30][31][32][33][34][35][36] trapping forces can achieve parts of this desired functionality; however, no single technique to our knowledge encompasses the scalability, flexibility and automation that allows single-cell chips to perform with the level of integration of computer circuits.Our approach has significant similarities with magnetic bubble memory technology 37 , which was originally developed to store memory and implement lo...

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On-chip manipulation and trapping of microorganisms using a patterned magnetic pathway

Cited by 25 publications

References 20 publications

Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor

Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor

Dynamic trajectory analysis of superparamagnetic beads driven by on-chip micromagnets

Magnetophoretic circuits for digital control of single particles and cells

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