The inertio-elastic planar entry flow of low-viscosity elastic fluids in micro-fabricated geometries

Rodd, Lucy E.; Scott, Timothy P.; Boger, David V.; Cooper-White, Justin J.; McKinley, Gareth H.

doi:10.1016/j.jnnfm.2005.04.006

Cited by 307 publications

(374 citation statements)

References 57 publications

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“…The ratio of these two competing non-linear forces is characterized using the elasticity number El (Wi/Re l relax m/ 2rR 2 ) (ref. 7). We expected that the particle focusing is maintained up to high flow rates, because the El value is as high as 224 for the 0.0005 (w/v)% DNA solution in the microtube of 50 mm diameter.…”

Section: Resultsmentioning

confidence: 99%

“…The Zimm relaxation time of unstained DNA adjusted to the present solution viscosity (2.1 cP) is estimated to be 0.14 s, based on a previous calculation in a 1 cP solvent (the relaxation time is proportional to medium viscosity) 6 . For comparison, the Zimm relaxation time of a flexible synthetic polymer solution (PEO with Mw ¼ 2 Â 10 6 g mol À 1 ) in a 2.1 cP solvent is 200-fold smaller than that of the DNA solution 39 , though the contour lengths of both polymers are nearly identical 1,7 .…”

Section: Methodsmentioning

confidence: 99%

“…Next, based on equation (7), we predicted the particle migration in 0.0005 wt% PEO (Mw ¼ 2 Â 10 6 g mol À 1 ) solution in 22 wt% glycerine aqueous solution (5 p.p.m. PEO) (l relax ¼ 0.71 ms and c/c* ¼ 0.006) 7,19,39 . The empirical parameter a p was determined by averaging two values ( À 0.34 and À 0.40) that correspond to the a p values obtained by fitting the experimental data presented in Supplementary Fig.…”

Section: Polymer Contribution To the Viscosity Of A Polymer Solution mentioning

confidence: 99%

“…The structural characteristics of DNA result in both larger coiled size at equilibrium, which is represented by radius of gyration (R g ), and longer relaxation time (l DNA ) than those of common synthetic flexible polymers [2][3][4] . For instance, the values of R g ¼ 0.53 mm and l DNA ¼ 140 ms, which were estimated in a 2.1 cP solvent for unstained double-stranded l-DNA 5,6 , are much larger than the respective values of 0.065 mm and 0.7 ms for a representative water-soluble synthetic polymer: poly(ethylene oxide) (PEO) (molecular weight (Mw) ¼ 2 Â 10 6 g mol À 1 ) of a similar contour length (see Methods for theoretical background) 6,7 . However, it is not well understood whether the unique structural characteristics of DNA make distinct differences in the non-Newtonian behaviours of its solution compared with synthetic polymers.…”

mentioning

confidence: 92%

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DNA-based highly tunable particle focuser

et al. 2013

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DNA is distinguished by both long length and structural rigidity. Classical polymer theories predict that DNA enhances the non-Newtonian elastic properties of its dilute solution more significantly than common synthetic flexible polymers because of its larger size and longer relaxation time. Here we exploit this property to report that under Poiseuille microflow, rigid spherical particles laterally migrate and form a tightly focused stream in an extremely dilute DNA solution (0.0005 (w/v)%). By the use of the DNA solution, we achieve highly efficient focusing (499.5%) over an unprecedented wide range of flow rates (ratio of maximum to minimum flow rates B400). This highly tunable particle-focusing technique can be used in the design of cost-effective portable flow cytometers, high-throughput cell analysis and also for cell sorting by size. We demonstrate that DNA is an efficient elasticity enhancer, which originates from its unique structural properties.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Polymer Contribution To the Viscosity Of A Polymer Solution mentioning

confidence: 99%

mentioning

confidence: 92%

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DNA-based highly tunable particle focuser

et al. 2013

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“…Figure 3b inset 51 ). Since Wi λ ∝ , the newly prepared PEO solution will show stronger elasticity than the PVP solution in a given flow condition.…”

Section: Methodsmentioning

confidence: 97%

Size-Based Separation of Particles and Cells Utilizing Viscoelastic Effects in Straight Microchannels

et al. 2015

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Viscoelasticity-induced particle migration has recently received increasing attention due to its ability to obtain high-quality focusing over a wide range of flow rates. However, its application is limited to low throughput regime since the particles can defocus as flow rate increases. Using an engineered carrier medium with constant and low viscosity and strong elasticity, the sample flow rates are improved to be one order of magnitude higher than those in existing studies. Utilizing differential focusing of particles of different sizes, here we present sheathless particle/cell separation in simple straight microchannels that possess excellent parallelizability for further throughput enhancement. The present method can be implemented over a wide range of particle/cell sizes and flow rates. We successfully separate small particles from larger particles, MCF-7 cells from red blood cells (RBCs), and Escherichia coli (E. coli) bacteria from RBCs in different straight microchannels. The proposed method could broaden the applications of viscoelastic microfluidic devices to particle/cell separation due to the enhanced sample throughput and simple channel design.Continuous manipulation and separation of particles and cells is important for a wide range of applications in biology, 1,2 medicine, 2,3 and industry. [4][5][6] Microfluidic systems have been proven to be promising tools for particle/cell manipulation with higher sensitivity and accuracy than their macroscale counterparts. The last decade has seen extensive development of microfluidic approaches for particle/cell manipulation that resort to immunocapture, 7 externally applied physical fields, [8][9][10][11][12][13][14][15][16][17][18] microfiltration, 19,20 gravitational sedimentation, 21 or deterministic lateral migration. 22,23 More recently, cross-streamline migration induced by the hydrodynamic effects of carrier media, such as inertia 24,25 and viscoelasticity, 26,27 has shown its promise for effective particle/cell manipulation without need of labeling and external force fields. Particles and cells can be separated based on the size-dependent nature of hydrodynamic forces. Briefly, the inertial lift scales as F a ∝ , where a is the particle diameter. There are several cell types of biological and clinical interest with separable size ranges: epithelial tumor cells (15-25 µm in diameter), blood cells (erythrocytes are 6-8 µm biconcave disks and peripheral blood lymphocytes are 7-10 µm in diameter), and bacteria (1-3 µm). Inertial migration in Newtonian fluids has been intensively studied and implemented in high-throughput label-free separation devices for cell separation. [28][29][30][31][32][33][34] Recently, particle migration induced by viscoelasticity has begun to attract increasing attention due to its simple focusing pattern and potential for achieving efficient focusing over a wide range of flow rates. 35,36 In a viscoelastic medium, elasticity coupled with non-negligible inertia will drive particles towards the channel centerline, whic...

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