Vesicle shape transformations driven by confined active filaments

Peterson, Matthew; Baskaran, Aparna; Hagan, Michael F.

doi:10.21203/rs.3.rs-448564/v1

Cited by 3 publications

(2 citation statements)

References 65 publications

(83 reference statements)

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“…In spite of these limitations, our results may support the view that some aspects of droplet migration through constrained environments would strongly rely upon mesoscopic physical ingredients, such as speed, elasticity, and adhesion forces rather than on the microscopic details of the physics involved. We finally mention that an alternative class of model systems, potentially useful for designing artificial swimmers, is that of active vesicles, which are built by encapsulating self-propelled particles within a soft membrane [63][64][65] . Such objects have been found to reproduce some features of motile cells, including membrane fluctuations and highly branched sub-micrometer protrusions, phenomena occurring at lengthscales usually inaccessible by exclusive meanfield-like approaches but often crucial in driving pathological processes (such as cancer metastasis) within highly confinedenvironments.…”

Section: Discussionmentioning

confidence: 99%

The crucial role of adhesion in the transmigration of active droplets through interstitial orifices

et al. 2023

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Active fluid droplets are a class of soft materials exhibiting autonomous motion sustained by an energy supply. Such systems have been shown to capture motility regimes typical of biological cells and are ideal candidates as building-block for the fabrication of soft biomimetic materials of interest in pharmacology, tissue engineering and lab on chip devices. While their behavior is well established in unconstrained environments, much less is known about their dynamics under strong confinement. Here, we numerically study the physics of a droplet of active polar fluid migrating within a microchannel hosting a constriction with adhesive properties, and report evidence of a striking variety of dynamic regimes and morphological features, whose properties crucially depend upon droplet speed and elasticity, degree of confinement within the constriction and adhesiveness to the pore. Our results suggest that non-uniform adhesion forces are instrumental in enabling the crossing through narrow orifices, in contrast to larger gaps where a careful balance between speed and elasticity is sufficient to guarantee the transition. These observations may be useful for improving the design of artificial micro-swimmers, of interest in material science and pharmaceutics, and potentially for cell sorting in microfluidic devices.

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Section: Discussionmentioning

confidence: 99%

The crucial role of adhesion in the transmigration of active droplets through interstitial orifices

et al. 2023

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“…In many other examples, biological materials are combined with active synthetic constituents with a hope to mimic various biological systems or even go beyond their functionality [17,18]. Here, an interesting example is a closed membrane enclosing biological micro-swimmers such as bacteria [19][20][21] or synthetic self-propelled particles [18,[22][23][24][25]. Active components inside the soft confinement exert forces on the surface, leading to highly dynamic nonequilibrium shape changes which resemble certain processes in living cells such as the formation of filopodia and lamellipodia [5,26,27], and active shape fluctuations of the membrane [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Dynamic shapes of floppy vesicles enclosing active Brownian particles with membrane adhesion

Gompper¹,

Fedosov²

2023

Preprint

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Recent advances in micro-and nano-technologies allow the construction of complex active systems from biological and synthetic materials. An interesting example is active vesicles, which consist of a membrane enclosing self-propelled particles, and exhibit several features resembling biological cells. We investigate numerically the behavior of active vesicles, where the enclosed self-propelled particles can adhere to the membrane. A vesicle is represented by a dynamically triangulated membrane, while the adhesive active particles are modelled as active Brownian particles (ABPs) that interact with the membrane via the Lennard-Jones potential. Phase diagrams of dynamic vesicle shapes as a function of ABP activity and particle volume fraction inside the vesicle are constructed for different strengths of adhesive interactions. At low ABP activity, adhesive interactions dominate over the propulsion forces, such that the vesicle attains near static configurations, with protrusions of membrane-wrapped ABPs having ring-like and sheet-like structures. At moderate particle densities and strong enough activities, active vesicles show dynamic highly-branched tethers filled with string-like arrangements of ABPs, which do not occur in the absence of particle adhesion to the membrane. At large volume fractions of ABPs, vesicles fluctuate for moderate particle activities, and elongate and finally split into two vesicles for large ABP propulsion strengths. We also analyze membrane tension, active fluctuations, and ABP characteristics (e.g., mobility, clustering), and compare them to the case of active vesicles with non-adhesive ABPs. The adhesion of ABPs to the membrane significantly alters the behavior of active vesicles, and provides an additional parameter for controlling their behavior.

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Vesicle shape transformations driven by confined active filaments

2021

Self Cite

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In active matter systems, deformable boundaries provide a mechanism to organize internal active stresses. To study a minimal model of such a system, we perform particle-based simulations of an elastic vesicle containing a collection of polar active filaments. The interplay between the active stress organization due to interparticle interactions and that due to the deformability of the confinement leads to a variety of filament spatiotemporal organizations that have not been observed in bulk systems or under rigid confinement, including highly-aligned rings and caps. In turn, these filament assemblies drive dramatic and tunable transformations of the vesicle shape and its dynamics. We present simple scaling models that reveal the mechanisms underlying these emergent behaviors and yield design principles for engineering active materials with targeted shape dynamics.

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Vesicle shape transformations driven by confined active filaments

Cited by 3 publications

References 65 publications

The crucial role of adhesion in the transmigration of active droplets through interstitial orifices

The crucial role of adhesion in the transmigration of active droplets through interstitial orifices

Dynamic shapes of floppy vesicles enclosing active Brownian particles with membrane adhesion

Vesicle shape transformations driven by confined active filaments

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