Microfluidic centrifuge based on a counterflow configuration

Pertaya-Braun, Natalya; Baier, Tobias; Hardt, Steffen

doi:10.1007/s10404-011-0875-5

Cited by 5 publications

(4 citation statements)

References 21 publications

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“…However, inertial focusing represents a passive technique for manipulating and separating cells on microscale without an external force or field . A few curved configurations were developed to enable the secondary flow − in microchannels. A baffled spiral microchannel is developed in this work to intensify the micromixing process, which is shown in Figure a.…”

Section: Experimental Detailsmentioning

confidence: 99%

Investigation of Mixing Performance in Passive Micromixers

Zhang

Feng

et al. 2016

Ind. Eng. Chem. Res.

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This work is focused on the mixing performance in passive microchannels. Experiments are performed to investigate the effect of inlet mixing angle and surface wettability on the micromixing efficiency in micromixers. The iodate–iodide testing reaction and a micro particle image velocimetry (micro-PIV) system are adopted to characterize the micromixing efficiency. The results demonstrate that the micromixing efficiency is enhanced as the inlet mixing angle increases. It is also illustrated that the mixing performance in hydrophobic microchannels is better compared to hydrophilic ones. To optimize the configuration of microchannels for better mixing, a novel baffled spiral micromixer is developed. The experiments show that the micromixing efficiency in the novel micromixer is significantly improved, compared to conventional ones.

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Section: Experimental Detailsmentioning

confidence: 99%

Investigation of Mixing Performance in Passive Micromixers

Zhang

Feng

et al. 2016

Ind. Eng. Chem. Res.

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“…They are utilized for on-chip microcentrifuges [8][9][10], to focus or separate particles [11][12][13], to manipulate cells [7,14], to trap particles [15,16], to enrich rare cells, e.g., circulating tumor cells [17,18], to fabricate micromixers [19][20][21], to synthesize size-controlled nanoparticles [22], or to extract plasma from blood [23,24]. All these works rely on the efficient generation of microvortices.…”

Section: Introductionmentioning

confidence: 99%

“…Passive microvortices are created by channel geometries like sudden expansions in microscale channels [7,12,15,18,19], cylindrical microcavities [35], trapezoidal side chambers [14], microbifurcations [28], embedded obstacles inside the flow channel [21,36,37], two counterflowing liquid streams [9] or at the boundary layer between sheath and center stream [22].…”

Section: Introductionmentioning

confidence: 99%

Microfluidic Vortex Enhancement for on-Chip Sample Preparation

et al. 2015

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In the past decade a large amount of analysis techniques have been scaled down to the microfluidic level. However, in many cases the necessary sample preparation, such as separation, mixing and concentration, remains to be performed off-chip. This represents a major hurdle for the introduction of miniaturized sample-in/answer-out systems, preventing the exploitation of microfluidic's potential for small, rapid and accurate diagnostic products. New flow engineering methods are required to address this hitherto insufficiently studied aspect. One microfluidic tool that can be used to miniaturize and integrate sample preparation procedures are microvortices. They have been successfully applied as microcentrifuges, mixers, particle separators, to name but a few. In this work, we utilize a novel corner structure at a sudden channel expansion of a microfluidic chip to enhance the formation of a microvortex. For a maximum area of the microvortex, both chip geometry and corner structure were optimized with a computational fluid dynamic (CFD) model. Fluorescent particle trace measurements with the optimized design prove Micromachines 2015, 6 240 that the corner structure increases the size of the vortex. Furthermore, vortices are induced by the corner structure at low flow rates while no recirculation is observed without a corner structure. Finally, successful separation of plasma from human blood was accomplished, demonstrating a potential application for clinical sample preparation. The extracted plasma was characterized by a flow cytometer and compared to plasma obtained from a standard benchtop centrifuge and from chips without a corner structure.

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“…31 In fact, many researchers capitalize on the high rotational frequency to provide particle sedimentation, fractionation, isolation, separation among others. 22,[32][33][34][35][36] Recent advances capitalize on microfluidic design to achieve passive valving and inertial focusing within the centrifugal platform. 37,38 Carboxylated microbeads are also recently utilized for specific biomolecular capture and extraction in a centrifugal platform.…”

Section: Introductionmentioning

confidence: 99%

Microfluidic size separation of cells and particles using a swinging bucket centrifuge

2015

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Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency.

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Microfluidic centrifuge based on a counterflow configuration

Cited by 5 publications

References 21 publications

Investigation of Mixing Performance in Passive Micromixers

Investigation of Mixing Performance in Passive Micromixers

Microfluidic Vortex Enhancement for on-Chip Sample Preparation

Microfluidic size separation of cells and particles using a swinging bucket centrifuge

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