Trapping self-propelled micromotors with microfabricated chevron and heart-shaped chips

Restrepo-Pérez, Laura; Soler, Lluís; Martínez-Cisneros, Cynthia S.; Sánchez, Samuel; Schmidt, Oliver G.

doi:10.1039/c3lc51419f

Cited by 37 publications

(45 citation statements)

References 34 publications

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“…35 This ratchet effect in effectively two-dimensional systems becomes more pronounced for large perimeter-to-surface ratios and therefore lets us envisage the design and manufacture of miniaturized devices to control the cell dynamics as well as the artificial microswimmer dynamics for selection, testing, concentration, separation [36][37][38] or trapping. 39,40 In this work, we demonstrate that, by properly texturing the sample borders, it is possible to tune the relative density of cells in the interior of a shallow chamber by diminishing the sperm density at its perimeter. In addition, we provide further insights on the motility of human sperm cells confined between two surfaces separated by $25 lm, a distance shorter than their own length, $60 lm.…”

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confidence: 78%

Disrupting the wall accumulation of human sperm cells by artificial corrugation

et al. 2015

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Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells ∼60 μm long, strongly confined to ∼25 μm shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.

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confidence: 78%

Disrupting the wall accumulation of human sperm cells by artificial corrugation

et al. 2015

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“…Restrepo-PØrez et al demonstrated the trapping of micromotors and the elimination of the need for external energy sources to control their motion. [169] The technique relies solely on steric boundaries present on microfluidic chips containing chevron and heart-shape engineered structures (Figure 17 B). Chevron-shaped structures with angles from 40 to 1408 were fabricated from PDMS, and showed a higher trapping efficiency than smaller angles, as previously predicted theoretically.…”

Section: Microchips and Physical Boundariesmentioning

confidence: 99%

Chemically Powered Micro‐ and Nanomotors

2014

Self Cite

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Chemically powered micro- and nanomotors are small devices that are self-propelled by catalytic reactions in fluids. Taking inspiration from biomotors, scientists are aiming to find the best architecture for self-propulsion, understand the mechanisms of motion, and develop accurate control over the motion. Remotely guided nanomotors can transport cargo to desired targets, drill into biomaterials, sense their environment, mix or pump fluids, and clean polluted water. This Review summarizes the major advances in the growing field of catalytic nanomotors, which started ten years ago.

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“…Active matter itself has been intensely explored over the last years, both for living systems as bacteria [4], spermatozoa [5] and mammals [6,7] or is system of artificial microswimmers [8][9][10][11][12][13] with various propulsion mechanisms [14][15][16][17] and a plethora of nonequilibrium pattern formation phenomena were discovered [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. At fixed system boundaries active system show distinct clustering and trapping behaviour [34][35][36][37][38][39][40][41][42][43][44][45] and can be expoited to * kaiser@thphy.uni-duesseldorf.de steer the motion of microrotors and microcarriers [46][47][48] of fixed shape.…”

Section: Introductionmentioning

confidence: 99%

Unusual swelling of a polymer in a bacterial bath

Kaiser

Löwen

2014

The Journal of Chemical Physics

105

104

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The equilibrium structure and dynamics of a single polymer chain in a thermal solvent is by now well-understood in terms of scaling laws. Here we consider a polymer in a bacterial bath, i.e. in a solvent consisting of active particles which bring in nonequilibrium fluctuations. Using computer simulations of a self-avoiding polymer chain in two dimensions which is exposed to a dilute bath of active particles, we show that the Flory-scaling exponent is unaffected by the bath activity provided the chain is very long. Conversely, for shorter chains, there is a nontrivial coupling between the bacteria intruding into the chain which may stiffen and expand the chain in a nonuniversal way. As a function of the molecular weight, the swelling first scales faster than described by the Flory exponent, then an unusual plateau-like behaviour is reached and finally a crossover to the universal Flory behaviour is observed. As a function of bacterial activity, the chain end-to-end distance exhibits a pronounced non-monotonicity. Moreover, the mean-square displacement of the center of mass of the chain shows a ballistic behaviour at intermediate times as induced by the active solvent. Our predictions are verifiable in two-dimensional bacterial suspensions and for colloidal model chains exposed to artificial colloidal microswimmers.

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Trapping self-propelled micromotors with microfabricated chevron and heart-shaped chips

Abstract: Catalytic micromotors are trapped in microfluidic chips containing chevron and heart-shaped PDMS structures.

Cited by 37 publications

References 34 publications

Disrupting the wall accumulation of human sperm cells by artificial corrugation

Disrupting the wall accumulation of human sperm cells by artificial corrugation

Chemically Powered Micro‐ and Nanomotors

Unusual swelling of a polymer in a bacterial bath

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