Coagulation of Particles in Shear Flow: Applications to Biological Cells

Potanin, Andrei; Verkhusha, Vladislav V.; Vrzheshch, P. V.

doi:10.1006/jcis.1993.1412

Cited by 8 publications

(13 citation statements)

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“…First-order kinetics of cell aggregation (eq 6) was consistent with the theory of coagulation of colloid particles in turbulent flow (36). The effect of C 0 on k a for cell aggregation (eq 7) was even stronger than the linear increase predicted by the theory for colloid particles, which may be due to an increased efficiency of cell-cell interactions at high cell concentrations (23,37).…”

Section: Discussionsupporting

confidence: 74%

Dynamic Cell Seeding of Polymer Scaffolds for Cartilage Tissue Engineering

Vunjak-Novakovic

Obradović

Martin

et al. 1998

Biotechnology Progress

512

347

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Cell seeding of three-dimensional polymer scaffolds is the first step of the cultivation of engineered tissues in bioreactors. Seeding requirements of large scaffolds to make implants for potential clinical use include: (a) high yield, to maximize the utilization of donor cells, (b) high kinetic rate, to minimize the time in suspension for anchorage-dependent and shear-sensitive cells, and (c) high and spatially uniform distribution of attached cells, for rapid and uniform tissue regeneration. Highly porous, fibrous polyglycolic acid scaffolds, 5-10 mm in diameter and 2-5 mm thick, were seeded with bovine articular chondrocytes in well-mixed spinner flasks. Essentially, all cells attached throughout the scaffold volume within 1 day. Mixing promoted the formation of 20-32-micron diameter cell aggregates that enhanced the kinetics of cell attachment without compromising the uniformity of cell distribution. The kinetics and possible mechanisms of cell seeding were related to the formation of cell aggregates by a simple mathematical model that can be used to optimize seeding conditions for cartilage tissue engineering.

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Section: Discussionsupporting

confidence: 74%

Dynamic Cell Seeding of Polymer Scaffolds for Cartilage Tissue Engineering

Vunjak-Novakovic

Obradović

Martin

et al. 1998

Biotechnology Progress

512

347

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“…This model, although restricted to the early stage of aggregation, has been accepted to describe a wide variety of systems, including latex spheres (Higuchi et al, 1963;Varennes et al, 1988), and hydrosols (Swift and Friedlander, 1964). Recently, more sophisticated models have also been developed (Potanin et al, 1993) in which ligand/receptor interaction and elasticity of platelets were incorporated into an analytical solution of lubrication theory.…”

Section: Introductionmentioning

confidence: 99%

Aggregation efficiency of activated normal or fixed platelets in a simple shear field: effect of shear and fibrinogen occupancy

Xia

Frojmovic

1994

Biophysical Journal

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Shear rate can affect protein adsorption and platelet aggregation by regulating both the collision frequency and the capture efficiency (alpha). These effects were evaluated in well defined shear field in a micro-couette for shear rate G = 10 - 1000 s-1. The rate of protein binding was independent of G, shown for adsorption of albumin to latex beads and PAC1 to activated platelets. The initial aggregation rate for ADP-activated platelets in citrated platelet-rich plasma followed second order kinetics at the initial platelet concentrations between 20,000 and 60,000/microliters. alpha values, which dropped nearly fivefold for a 10-fold increase in G, were approximately proportional to G-1, contrary to a minor drop predicted by the theory that includes protein cross-bridging. Varying ADP concentration did not change alpha of maximally activated platelet subpopulations, suggesting that aggregation between unactivated and activated platelets is negligible. Directly blocking the unoccupied but activated GPIIb-IIIa receptors without affecting pre-bound Fg on "RGD"-activated, fixed platelets (AFP) by GRGDSP or Ro 43-5054 eliminated aggregation, suggesting that cross-bridging of GPIIb-IIIa on adjacent platelets by fibrinogen mediates aggregation. Alpha for AFP remained maximal (approximately 0.24) over 25-75% Fg occupancy, otherwise decreasing rapidly, with a half-maximum occurring at around 2% occupancy, suggesting that very few bound Fg were required to cause significant aggregation.

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“…The capture efficiency is predicted theoretically by Potanin et al (1993), using a force balance between fluid, colloidal, and biological forces. They predict a plateau region where the capture efficiency is relatively constant for shear rates between 10 and 1000 s À1 : According to our model, the peak capture probability is near one for a wide range of low-to-moderate shear rates, and so the capture efficiency should be nearly constant for those shear rates as well.…”

Section: Discussionmentioning

confidence: 99%

“…The densities of unoccupied and occupied receptors change with the time from activation, making the time since activation a factor in determining the probability that a collision between activated platelets results in the formation of a doublet. Previous mathematical models for the aggregation probability for platelets have not taken into account the effects of changing receptor occupancy (Potanin et al, 1993;Tandon & Diamond, 1997).…”

Section: Introductionmentioning

confidence: 99%