Depletion flocculation in dispersions of sterically-stabilised particles (“soft spheres”)

Vincent, Brian; Edwards, J. H.; Emmett, Simon; Jones, Andrew

doi:10.1016/0166-6622(86)80317-1

Cited by 367 publications

(396 citation statements)

References 23 publications

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“…The main difficulty when calculating such energies between RBC and EC is that both cells have a glycocalyx, which can be penetrated by the depleted polymers, thereby reducing the effective size of the depletion layer (19). Thus, for two adjacent cells with soft surfaces at a separation distance d, a combined glycocalyx thickness ␦ t , a depletion layer thickness ⌬, and a combined penetration p t of the polymers into the adjacent glycocalyces, the reduction in the free energy per area caused by depletion interaction is approximately given by the following,…”

Section: Discussionmentioning

confidence: 99%

Specific Binding of Red Blood Cells to Endothelial Cells Is Regulated by Nonadsorbing Macromolecules

Yang

Koo

Lin

et al. 2010

Journal of Biological Chemistry

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Abnormal adhesion of red blood cells to the endothelium has been linked to the pathophysiology of several diseases associated with vascular disorders. Various biochemical changes, including phosphatidylserine exposure on the outer membrane of red blood cells as well as plasma protein levels, have been identified as being likely to play a key role, but the detailed interplay between plasma factors and cellular factors remains unknown. It has been proposed that the adhesionpromoting effect of plasma proteins originates from ligand interaction, but evidence substantiating this assumption is often missing. In this work, we identified an alternative pathway by demonstrating that nonadsorbing macromolecules can also have a marked impact on the adhesion efficiency of red blood cells with enhanced phosphatidylserine exposure to endothelial cells. It is concluded that this adhesion-promoting effect originates from macromolecular depletion interaction and thereby presents an alternative mechanism by which plasma proteins could regulate cell-cell interactions. These findings should thus be of potential value for a detailed understanding of the pathophysiology of diseases associated with vascular complications and might be applicable to a wide range of cellcell interactions in plasma or plasma-like media. The adhesion of red blood cells (RBC)2 to endothelial cells (EC) is usually insignificant. However, increased RBC adhesion to endothelial cells has been observed in various clinical states such as sickle cell disease, ␤-thalassemia, and diabetes mellitus, and the degree of RBC-EC adhesiveness has been linked to the vascular complications associated with these diseases (1-5). There is now general agreement that various cell surface alterations control the increased RBC adhesiveness in such disease states. For example, an enhanced phosphatidylserine (PS) exposure on the outer leaflet of the RBC membrane has been linked to abnormal RBC-EC adhesion in sickle cell disease, hereditary hydrocytosis, and chronic uremia (6 -8). Usually this anionic phospholipid is located exclusively on the inner leaflet of the RBC membrane but is translocated to the outer leaflet in hemoglobinopathies and oxidative stress states (9). The role of PS in adhesion has not been fully understood, but RBC with enhanced PS exposure have been identified to establish specific interactions with EC or the endothelial matrix via several receptors including thrombospondin, ␣ V ␤ 3 , CD36, and PS receptor (6, 10, 11).Moreover, several plasma factors have been identified to be involved in abnormal RBC adhesion to EC. For example, fibrinogen enhances the adhesion of pathological RBC to EC (12, 13), which is consistent with the observation that the onset of vaso-occlusive crisis in sickle cell disease is always accompanied by a temporally elevated level of this acute phase protein (12,14). However, the underlying mechanisms behind the increased adhesion efficiency in the presence of this acute phase protein remain obscure. It has been suggested that fibrinogen acts...

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Section: Discussionmentioning

confidence: 99%

Specific Binding of Red Blood Cells to Endothelial Cells Is Regulated by Nonadsorbing Macromolecules

Yang

Koo

Lin

et al. 2010

Journal of Biological Chemistry

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“…Other adlayer configurations (e.g., block copolymers) are better modeled using alternate expressions provided in Ref. 69. As predicted, such dispersions can be rendered unstable when solvent conditions become poor (i.e., Ͼ 0.5).…”

Section: (3) Steric Forcesmentioning

confidence: 99%

“…68 When modeling homopolymer adsorption, a pseudohomopolymer model 69 is used to describe the mixing interactions that occur in the region, ␦ Ͻ h Ͻ 2␦, while the uniform segment model describes the mixing and elastic interactions that occur at smaller separations, h Ͻ ␦. The pseudohomopolymer model accounts for chain conformations other than tails (i.e., trains and loops) that are expected for such species.…”

Section: (3) Steric Forcesmentioning

confidence: 99%

Colloidal Processing of Ceramics

Lewis

2000

Journal of the American Ceramic Society

1,205

640

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Colloidal processing of ceramics is reviewed with an emphasis on interparticle forces, suspension rheology, consolidation techniques, and drying behavior. Particular attention is given to the scientific concepts that underpin the fabrication of particulate-derived ceramic components. The complex interplay between suspension stability and its structural evolution during colloidal processing is highlighted.

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“…While prior studies have described several aspects of RBC adhesion in normal and pathologic states, none appears to have considered depletion interaction as a non-specific force for cellsurface adhesion. Conversely, depletion mediated interactions are commonly considered in the general field of colloid chemistry, and several previous reports have dealt with the experimental and theoretical aspects of depletion aggregation, often termed depletion flocculation [3][4][5][6][7]. More recently, depletion interaction as an attractive force in polymer-induced RBC aggregation has been considered, with results indicating that polymer depletion plays a major role in reversible aggregation of RBC [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Within this layer the polymer concentration is lower than in the bulk phase. Thus, as two particles approach, the difference of solvent chemical potential (i.e., the osmotic pressure difference) between the intercellular polymer-poor depletion zone and the bulk phase results in solvent displacement into the bulk phase and hence depletion interaction [5]. Due to this interaction, an attractive force develops that tends to minimize the polymer-reduced space between the cells, thus resulting in flocculation or aggregation.…”

Section: Introductionmentioning

confidence: 99%

Depletion interactions in polymer solutions promote red blood cell adhesion to albumin-coated surfaces

Neu

Meiselman²

2006

Biochimica et Biophysica Acta (BBA) - General Subjects

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The effects of concentration and molecular weight of neutral dextrans on the adhesion of human red blood cells (RBC) to albumin-coated glass have been investigated using a parallel-plate flow chamber. Results indicate that the adhesion is markedly increased in the presence of 70 kDa and 500 kDa dextran, with this increase reflected by both the number of cells adhering and the strength of the adhesion. This increased adhesiveness is attributed to reduced surface concentrations of the large polymers and hence attractive forces due to depletion interaction. Depletion interaction brings the adjacent surfaces closer, leading to an increased number of binding sites available to the cell and thus more efficient and stronger adhesion of single cells. Our results suggest that depletion might play a role in other specific cell-cell or cell-surface interactions via initiating close contacts to allow specific binding.

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Depletion flocculation in dispersions of sterically-stabilised particles (“soft spheres”)

Cited by 367 publications

References 23 publications

Specific Binding of Red Blood Cells to Endothelial Cells Is Regulated by Nonadsorbing Macromolecules

Specific Binding of Red Blood Cells to Endothelial Cells Is Regulated by Nonadsorbing Macromolecules

Colloidal Processing of Ceramics

Depletion interactions in polymer solutions promote red blood cell adhesion to albumin-coated surfaces

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