LXXV. <i>A dynamical theory of diffusion for non-electrolytes and the molecular mass of albumin</i>

Sutherland, William

doi:10.1080/14786440509463331

Cited by 581 publications

(373 citation statements)

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“…Also, RBCs can obscure some of the fluorescent signal of the particles. Despite the relatively large error in determining the particle position at short timescales, the calculated values for the water cases are of the same order of magnitude as the Brownian diffusivities calculated using the Stokes-Einstein-Sutherland equation (54). As expected, the smaller the particle size, the higher the diffusivity in water.…”

Section: Margination Velocity and Effective Diffusivitysupporting

confidence: 68%

Direct Tracking of Particles and Quantification of Margination in Blood Flow

Carboni

Bognet

Bouchillon

et al. 2016

Biophysical Journal

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Margination refers to the migration of particles toward blood vessel walls during blood flow. Understanding the mechanisms that lead to margination will aid in tailoring the attributes of drug-carrying particles for effective drug delivery. Most previous studies evaluated the margination propensity of these particles via an adhesion mechanism, i.e., by measuring the number of particles that adhered to the channel wall. Although particle adhesion and margination are related, adhesion also depends on other factors. In this study, we quantified the margination propensity of particles of varying diameters (0.53, 0.84, and 2.11 mm) and apparent wall shear rates (30, 61, and 121 s À1 ) by directly tracking fluorescent particles flowing through a microfluidic channel. The margination parameter, M, is defined as the total number of particles found within the cell-free layers normalized by the total number of particles that passed through the channel. In this study, an M-value of 0.2 indicated no margination, which was observed for all particle sizes in water. In the case of blood, larger particles were found to have higher M-values and thus marginated more effectively than smaller particles. The corresponding M-values at the device outlet were 0.203, 0.223, and 0.285 for 0.53-, 0.84-, and 2.11-mm particles, respectively. At the inlet, the M-values for all particle sizes in blood were <0.2, suggesting that non-fully-developed flow and constriction may lead to demargination. For particle velocities transverse to the flow direction (v y ), all particle sizes showed a larger standard deviation of v y as well as a higher effective diffusivity when the particles were suspended in blood relative to water. These higher values are attributed to collisions between the blood cells and particles, further supporting recent simulation results. In terms of flow rates, for a given particle size, the higher the flow rate, the higher the M-value.

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Section: Margination Velocity and Effective Diffusivitysupporting

confidence: 68%

Direct Tracking of Particles and Quantification of Margination in Blood Flow

Carboni

Bognet

Bouchillon

et al. 2016

Biophysical Journal

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“…If the domain deformation is negligible during its Brownian motion, its diffusion coefficient equals the product of the Boltzmann constant, the temperature, and the reciprocal of the drag coefficient. 5,6) Thus, if we use the previous formula to calculate the diffusion coefficient of the domain embedded in the 2D near-critical binary fluid mixture, the calculation result should be smaller than the observed diffusion coefficient, according to our results valid for the weak preferential attraction.…”

Section: Discussionsupporting

confidence: 54%

“…Modeling a membrane protein as a rigid disk embedded in a flat fluid membrane, some researchers calculated its drag coefficient, [1][2][3][4] which is related to its diffusion coefficient, accessible more readily in experiments. [5][6][7] In the biomembrane, some minor lipid constituents are thought to be concentrated at domains called lipid rafts. [8][9][10] Similar domains in some artificial membranes are larger and circular.…”

Section: Introductionmentioning

confidence: 99%

Drag Coefficient of a Raftlike Domain Embedded in a Fluid Membrane Being a Near-Critical Binary Mixture

Fujitani

2013

J. Phys. Soc. Jpn.

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We consider a circular liquid domain in a flat fluid membrane surrounded by three-dimensional fluids, and assume that the membrane outside the domain is a two-dimensional near-critical binary fluid mixture. The membrane viscosity outside the domain is assumed to be uniform, irrespective of the local composition, and to be the same as that of the domain. Using the Gaussian free-energy functional, we show that the drag coefficient of the domain can be decreased by the preferential attraction between the domain and a component of the mixture, unlike that of a rigid sphere in a three-dimensional near-critical binary fluid mixture studied recently.

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“…Diffusion in three dimensions has been well understood since 1905, when two authors showed that the motion of particles suspended in a fluid is related to the fluid's viscosity [1,2]. This observation has been generalized in a technique called microrheology, which measures the thermal motion of tracer particles introduced in a viscoelastic material.…”

mentioning

confidence: 99%

Two-Particle Microrheology of Quasi-2D Viscous Systems

2006

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We study the spatially correlated motions of colloidal particles in a quasi-2D system (Human Serum Albumin (HSA) protein molecules at an air-water interface) for different surface viscosities ηs. We observe a transition in the behavior of the correlated motion, from 2-D interface dominated at high ηs to bulk fluid-dependent at low ηs. The correlated motions can be scaled onto a master curve which captures the features of this transition. This master curve also characterizes the spatial dependence of the flow field of a viscous interface in response to a force. The scale factors used for the master curve allow for the calculation of the surface viscosity ηs that can be compared to one-particle measurements.PACS numbers: 83.10. Mj, 87.68.+z, 87.16.Dg Diffusion in three dimensions has been well understood since 1905, when two authors showed that the motion of particles suspended in a fluid is related to the fluid's viscosity [1,2]. This observation has been generalized in a technique called microrheology, which measures the thermal motion of tracer particles introduced in a viscoelastic material. From the motions of the particles, the material dependent properties can be determined, such as the elastic modulus, G ′ (ω), and the viscous modulus, G ′′ (ω) [3]. This has been applied to measure the viscoelasticity of bulk materials such as polymer solutions [4], biomaterials [5] and hydrogels [6]. A closely related question is the motion of tracer particles in a two-dimensional system such as lipid molecules at an air-water interface [7] or lipid rafts in cell membranes [8]. For example, in a purely viscous 2-D system, one might imagine that the diffusive properties are related to the two-dimensional viscosity, and that by following the motion of tracer particles one could determine this viscosity. However, in most cases of practical interest, a strictly two-dimensional surface is an idealization and in reality the surface is adjacent to three-dimensional fluid reservoirs. For example, recent experiments study diffusion in biological systems such as cell membranes [8,9] which are surrounding a 3-D cell and immersed in a 3-D fluid. This coupling modifies the behavior of tracer particles and makes interpretation of the results trickier [10,11,12].Furthermore, in many cases in 3D, tracers are known to modify the structure of the medium in their vicinity, leading to erroneous measurements of rheological quantities [13]. Another possibility is that pre-existing inhomogeneities such as pores in an otherwise rigid material can entrain the tracers, resulting in measurements that underestimate the bulk viscoelasticity of the material in question [5]. To overcome these difficulties, a new method known as two-particle microrheology has been established [13], which looks at the cross-correlated thermal motions of pairs of particles. The correlated motion of two beads is driven by long-wavelength modes in the system, and is therefore independent of the local environment of the tracers. While two-particle microrheology has been a...

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LXXV. A dynamical theory of diffusion for non-electrolytes and the molecular mass of albumin

Cited by 581 publications

References 0 publications

Direct Tracking of Particles and Quantification of Margination in Blood Flow

Direct Tracking of Particles and Quantification of Margination in Blood Flow

Drag Coefficient of a Raftlike Domain Embedded in a Fluid Membrane Being a Near-Critical Binary Mixture

Two-Particle Microrheology of Quasi-2D Viscous Systems

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