Depletion attraction in colloidal and bacterial systems

Zhang, Hong; Kong, Dongyang; Zhang, Wenchao; Liu, Huaqing

doi:10.3389/fmats.2023.1206819

Cited by 3 publications

(1 citation statement)

References 140 publications

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“…Theories have also been further developed to cover more complex systems like those containing interacting depletants [ 53 , 54 , 55 , 56 ], multiple depletant types [ 57 ], surfactants [ 57 , 58 , 59 ], polymer brushes [ 60 ], or that exhibit multi-body effects [ 61 , 62 , 63 , 64 ]. Theories have also addressed the case of active colloids immersed in a bath of passive depletants [ 65 ], nanobubbles [ 66 ], nanoparticles [ 67 , 68 , 69 , 70 , 71 ], microgels [ 72 ], and bacterial systems [ 73 ]. One should also mention the theoretical efforts intended to characterize the depletion phenomena in confined domains [ 74 , 75 ], as well as near dielectric discontinuities [ 76 ] and in shear conditions [ 77 ].…”

Section: Introductionmentioning

confidence: 99%

Depletion Interactions at Interfaces Induced by Ferromagnetic Colloidal Polymers

Cerdà,

Batle,

Bona-Casas

et al. 2024

Polymers

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The pair-interaction force profiles for two non-magnetic colloids immersed in a suspension of ferromagnetic colloidal polymers are investigated via Langevin simulations. A quasi-two-dimensional approach is taken to study the interface case and a range of colloidal size ratios (non-magnetic:magnetic) from 6:1 up to 20:1 have been considered in this work. Simulations show that when compared with non-magnetic suspensions, the magnetic polymers strongly modify the depletion force profiles leading to strongly oscillatory behavior. Larger polymer densities and size ratios increase the range of the depletion forces, and in general, also their strength; the force barrier peaks at short distances show more complex behavior. As the length of the ferromagnetic polymers increases, the force profiles become more regular, and stable points with their corresponding attraction basins develop. The number of stable points and the distance at which they occur can be tuned through the modification of the field strength H and the angle θ formed by the field and the imaginary axis joining the centers of the two non-magnetic colloids. When not constrained, the net forces acting on the two colloids tend to align them with the field till θ=0∘. At this angle, the force profiles turn out to be purely attractive, and therefore, these systems could be used as a funneling tool to form long linear arrays of non-magnetic particles. Torsional forces peak at θ=45∘ and have minimums at θ=0∘ as well as θ=90∘ which is an unstable orientation as slight deviations will evolve towards θ→0∘. Nonetheless, results suggest that the θ=90∘ orientation could be easily stabilized in several ways. In such a case, the stable points that the radial force profiles exhibit for this orthogonal orientation to the field could be used to control the distance between the two large colloids: their position and number can be controlled via H. Therefore, suspensions made of ferromagnetic colloidal polymers can be also useful in the creation of magnetic colloidal tweezers or ratchets. A qualitative explanation of all the observed phenomena can be provided in terms of how the geometrical constraints and the external field modify the conformations of the ferromagnetic polymers near the two large particles, and in turn, how both factors combine to create unbalanced Kelvin forces that oscillate in strength with the distance between the two non-magnetic colloids.

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Section: Introductionmentioning

confidence: 99%

Depletion Interactions at Interfaces Induced by Ferromagnetic Colloidal Polymers

Cerdà,

Batle,

Bona-Casas

et al. 2024

Polymers

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Depletion forces beyond the diluted limit

de los Santos-López,

Ramírez-Guízar,

Pérez-Ángel

et al. 2024

Physica A: Statistical Mechanics and its Applications

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Salt Gradient-Induced Phoresis of Vesicles and Enhanced Membrane Fusion in a Crowded Milieu

Yadav,

Sivoria,

Maiti

2024

J. Phys. Chem. B

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Phoresis of biocolloidal objects in response to chemical gradients is a matter of interest among diverse scientific disciplines owing to their importance in the spatiotemporal orchestration of biochemical processes. Although there are reports of soft matter transport/phoresis in the gradient of ions or salts in the aqueous system, their phoretic behavior in the presence of macromolecular crowder is largely unexplored. Notably, cellular cytoplasm is illustrated as a crowded milieu and thereby understanding biomolecular phoresis in the presence of polymeric macromolecules would endorse phoretic behavior in a biomimetic environment. Here, we report the phoresis-induced enhanced aggregation and fusion of vesicles in gradients of monovalent (NaCl) and divalent salt (MgCl 2 ), in the presence of polymeric crowder, polyethylene glycol of molecular weight 400 (PEG 400). Apart from diffusiophoresis, depletion force plays a crucial factor in crowded environments to control localized vesicle aggregation in a salt gradient. This demonstration will potentially show the pathway to future research related to spatiotemporally correlated liposomal transport and membrane-dependent function (such as content mixing and signaling) in a physiologically relevant crowded environment.

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Depletion attraction in colloidal and bacterial systems

Cited by 3 publications

References 140 publications

Depletion Interactions at Interfaces Induced by Ferromagnetic Colloidal Polymers

Depletion Interactions at Interfaces Induced by Ferromagnetic Colloidal Polymers

Depletion forces beyond the diluted limit

Salt Gradient-Induced Phoresis of Vesicles and Enhanced Membrane Fusion in a Crowded Milieu

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