Development of sorting, aligning, and orienting motile sperm using microfluidic device operated by hydrostatic pressure

Seo, Duckbong; Ağca, Yüksel; Feng, Z. C.; Critser, John K.

doi:10.1007/s10404-006-0142-3

Cited by 94 publications

(61 citation statements)

References 20 publications

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“…However, the red sperms swim upstream against the flow of seminal plasma. The selfmovement of sperm against flow direction has been reported [17]. As to the collapse of the semen drop, the similar wash-away sperms were observed when the voltage was on and we did not observe the sperms swim against the fluidic flow.…”

Section: Resultssupporting

confidence: 81%

A Sperm Testing Device on a Liquid Crystal and Polymer Composite Film

Lin¹,

Chu²,

Chu³

et al. 2013

J Nanomed Nanotechol

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Developing a handy sperm testing device is important since sperm quality is a significant factor for fertility potential. In this paper, we demonstrate a sperm testing device based on a switchable surface, a liquid crystal and polymer composite film (LCPCF). The wettability of LCPCF is electrically switchable due to the electrically tunable orientations of liquid crystal molecules. In experiments, two motions of a semen drop on switchable surface of LCPCF are observed: back-and-forth stretches and collapses of semen drops. The better quality spermatozoa results in back-and-forth stretches of a semen drop on LCPCF; otherwise, the semen drop collapses. The motility and concentration of semen can also be sensed by the stretch distance and collapse distance of semen drops, respectively. The mechanism of back-and-forth stretches of semen drops results from fertile sperms swimming against the flow with the periodic changes of the orientation of LC molecules with pulsed voltages. The mechanism of collapses of semen drops results from the washed-away infertile sperms which are deposited on LCPCF and then re-modify surface of LCPCF. Potential applications for this device include sperm testers and microfluidic devices for Assisted Reproductive Technology.

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Section: Resultssupporting

confidence: 81%

A Sperm Testing Device on a Liquid Crystal and Polymer Composite Film

Lin¹,

Chu²,

Chu³

et al. 2013

J Nanomed Nanotechol

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“…Using our predicted geometries, which, incidentally, were in general agreement with very recent theoretical works [30,31], rows of ∪-shaped obstacles were designed and a high sperm cell concentration was achieved, demonstrating that the interaction of the cells with the rounded walls leads to the rectification and control of the sperm movement without trapping the cells. Our noninvasive procedure is an alternative efficient method to achieve sperm sorting [32,33] and directioning in channels [34] . We have also shown that a characterization of the specific strategy for swimming along walls of each microswimmer species and of its behavior near corners and along edges, together with a knowledge of the motility parameters under 2D confinement will be crucial for designing and modeling efficient biomedical devices.…”

mentioning

confidence: 99%

Geometrical guidance and trapping transition of human sperm cells

et al. 2014

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The guidance of human sperm cells under confinement in quasi 2D microchambers is investigated using a purely physical method to control their distribution. Transport property measurements and simulations are performed with dilute sperm populations, for which effects of geometrical guidance and concentration are studied in detail. In particular, a trapping transition at convex angular wall features is identified and analyzed. We also show that highly efficient microratchets can be fabricated by using curved asymmetric obstacles to take advantage of the spermatozoa specific swimming strategy.PACS numbers: 87.17. Jj, 87.18.Hf, 87.17.Aa, 87.17.Rt Understanding sperm dynamics under confining microgeometries is a general problem and a major challenge both from the basic biophysics and the complex fluids points of view. It is also crucial for microfluidics and biomedical control applications. Our knowledge of the swimming cell motilities in unbounded media cannot be directly extrapolated to their behavior in complex environments such as those found in the oviduct or in the labon-a-chip microfluidic devices used to control and analyze small samples or for in-vitro reproduction procedures. In these cases, the characteristic length scales are of the same order as the cell size, i.e. a few micrometers. Under these circumstances, confined self-propelled microorganisms undergo substantial changes in their locomotion habits, adapting their dynamics to intricate porous media or to solid surfaces vicinity [1], reducing their speed close to boundaries [2] or adjusting their morphology and motility in very narrow channels [3].It has been shown that microswimmers with very different propulsion systems are similarly attracted to the walls and to swim parallel to the surface [2,[4][5][6][7][8][9][10][11]. It is believed that this attractive force has hydrodynamic origin although other possible mechanisms have been proposed [12][13][14]. Several models have been introduced to describe the swimming along surfaces (see Ref.[15] and references therein). Interestingly, the direct observation of the cell-wall attraction (see Fig. 1) have led to the design of ratchet devices that guide and sort self-propelled cells using asymmetric obstacles [16,17]. In particular, different microfluidic devices have been created to either increase sperm cell quality or enhance their concentration [18][19][20]. The creation of inhomogeneous distributions of swimmer populations via asymmetric obstacles has been shown to be particularly efficient for run-and-tumble bacteria [16,[21][22][23]. Alternative ways of achieving nonuniform distributions have also been obtained combining symmetric funnels and flux [24]. Nowadays, numerous theoretical treatments are available to account for the effects of asymmetric obstacles on active particles distributions [25][26][27][28]. Tumbles, rotational diffusion and collisions are efficient mechanisms for separating the cells from the surface, thus permitting bacteria to be reinserted into the bulk of the confining micro...

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“…15.7b) All the sperms are then flushed by such a fluidic flow. However, the fertile sperms swim upstream against the fluidic flow because of the nature of the fertile sperms [23]. (Figure 15.7b) When we turn off the voltage, the LC molecules reorientate back along y-direction owing to the elastically essential properties of LC and the anchoring force of polymer grains.…”

Section: Sperm Testing Devices Using Droplet Manipulationmentioning

confidence: 99%

Liquid Crystals for Bio-medical Applications

Lin

2014

Topics in Applied Physics

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Thermotropic nematic LCs can modulate light in phases, amplitudes, and polarizations [1]. Many photonic applications based LCs have developed, such as displays, electro-optical switches, lenses, optical vortex generators, variable optical attenuations, solar cells and so on. Thermotropic nematic LCs have great potential in bio-medical applications. In this session, we mainly introduce two the bio-medical applications based on thermotropic nematic LCs: biosensors and ophthalmic lenses. In biosensors, the key is interfacial interactions between biosamples and LC molecules. We will introduce a LC and polymer complex system, the LC and polymer composite film (LCPCF), whose surface free energy is electrically switchable. LCPCF can help to test the sperm quality and high-density-lipoprotein (HDL). In ophthalmic applications, we will introduce the challenges and requirements for design of ophthalmic lenses. A polarizer-free LC lens with large aperture size is also introduced. Biosensors Using Nematic Liquid CrystalsIn general, interfacial interactions between LCs and bio-samples (or sensing targets) are the key to design a biosensor using nematic LCs [2][3][4][5][6][7]. Such an interfacial interaction often causes the re-orientations of LC molecules at the interface. As a result, optical properties of LC change and the change of the orientation of LC can be read out by observing under a polarizing microscopy. LC can optically amplify the biological binding events and help us to study the biology. The main approach is to immobilize thermotropic nematic LC onto a solid surface as a sensing interface for bio-samples. 5CB is a commonly used a LC material for biosensing. In the literatures, 5CB has been proved for sensing many bio-samples,

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Development of sorting, aligning, and orienting motile sperm using microfluidic device operated by hydrostatic pressure

Cited by 94 publications

References 20 publications

A Sperm Testing Device on a Liquid Crystal and Polymer Composite Film

A Sperm Testing Device on a Liquid Crystal and Polymer Composite Film

Geometrical guidance and trapping transition of human sperm cells

Liquid Crystals for Bio-medical Applications

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