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The margination propensity of spherical particles for vascular targeting in the microcirculation.

Gentile F, Curcio A, Indolfi C, Ferrari M, Decuzzi P - J Nanobiotechnology (2008)

Bottom Line: In horizontal capillaries, margination is mainly due to the gravitational force for particles with d > 200 nm and V approximately s increases with d4; whereas for smaller particles V approximately s increases with d3.In vertical capillaries, since the particles are heavier than the fluid they would tend to marginate towards the walls in downward flows and towards the center in upward flows, with V approximately s increasing with d9/2.However, the margination in vertical capillaries is predicted to be much smaller than in horizontal capillaries.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center of Bio-/Nanotechnology and -/Engineering for Medicine University of Magna Graecia at Catanzaro, Viale Europa - Loc, Germaneto, 88100, Catanzaro, Italy. Paolo.Decuzzi@uth.tmc.edu.

ABSTRACT
The propensity of circulating particles to drift laterally towards the vessel walls (margination) in the microcirculation has been experimentally studied using a parallel plate flow chamber. Fluorescent polystyrene particles, with a relative density to water of just 50 g/cm3comparable with that of liposomal or polymeric nanoparticles used in drug delivery and bio-imaging, have been used with a diameter spanning over three order of magnitudes from 50 nm up to 10 mum. The number n approximately s of particles marginating per unit surface have been measured through confocal fluorescent microscopy for a horizontal chamber, and the corresponding total volume V approximately s of particles has been calculated. Scaling laws have been derived as a function of the particle diameter d. In horizontal capillaries, margination is mainly due to the gravitational force for particles with d > 200 nm and V approximately s increases with d4; whereas for smaller particles V approximately s increases with d3. In vertical capillaries, since the particles are heavier than the fluid they would tend to marginate towards the walls in downward flows and towards the center in upward flows, with V approximately s increasing with d9/2. However, the margination in vertical capillaries is predicted to be much smaller than in horizontal capillaries. These results suggest that, for particles circulating in an external field of volume forces (gravitation or magnetic), the strategy of using larger particles designed to marginate and adhere firmly to the vascular walls under flow could be more effective than that of using particles sufficiently small (d < 200 nm) to hopefully cross a discontinuous endothelium.

No MeSH data available.


Related in: MedlinePlus

The margination trajectory of a spherical particle within a laminar flow.
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Figure 3: The margination trajectory of a spherical particle within a laminar flow.

Mentions: where ⟨h⟩ is the average separation distance of the particle from the wall (see Fig. 3). Integrating (2) over an initial separation distance ⟨Ho⟩, and observing that when at ⟨Ho⟩ the particle would move longitudinally by the distance L in a time Δt = L/(S⟨Ho⟩), it follows that


The margination propensity of spherical particles for vascular targeting in the microcirculation.

Gentile F, Curcio A, Indolfi C, Ferrari M, Decuzzi P - J Nanobiotechnology (2008)

The margination trajectory of a spherical particle within a laminar flow.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2563017&req=5

Figure 3: The margination trajectory of a spherical particle within a laminar flow.
Mentions: where ⟨h⟩ is the average separation distance of the particle from the wall (see Fig. 3). Integrating (2) over an initial separation distance ⟨Ho⟩, and observing that when at ⟨Ho⟩ the particle would move longitudinally by the distance L in a time Δt = L/(S⟨Ho⟩), it follows that

Bottom Line: In horizontal capillaries, margination is mainly due to the gravitational force for particles with d > 200 nm and V approximately s increases with d4; whereas for smaller particles V approximately s increases with d3.In vertical capillaries, since the particles are heavier than the fluid they would tend to marginate towards the walls in downward flows and towards the center in upward flows, with V approximately s increasing with d9/2.However, the margination in vertical capillaries is predicted to be much smaller than in horizontal capillaries.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center of Bio-/Nanotechnology and -/Engineering for Medicine University of Magna Graecia at Catanzaro, Viale Europa - Loc, Germaneto, 88100, Catanzaro, Italy. Paolo.Decuzzi@uth.tmc.edu.

ABSTRACT
The propensity of circulating particles to drift laterally towards the vessel walls (margination) in the microcirculation has been experimentally studied using a parallel plate flow chamber. Fluorescent polystyrene particles, with a relative density to water of just 50 g/cm3comparable with that of liposomal or polymeric nanoparticles used in drug delivery and bio-imaging, have been used with a diameter spanning over three order of magnitudes from 50 nm up to 10 mum. The number n approximately s of particles marginating per unit surface have been measured through confocal fluorescent microscopy for a horizontal chamber, and the corresponding total volume V approximately s of particles has been calculated. Scaling laws have been derived as a function of the particle diameter d. In horizontal capillaries, margination is mainly due to the gravitational force for particles with d > 200 nm and V approximately s increases with d4; whereas for smaller particles V approximately s increases with d3. In vertical capillaries, since the particles are heavier than the fluid they would tend to marginate towards the walls in downward flows and towards the center in upward flows, with V approximately s increasing with d9/2. However, the margination in vertical capillaries is predicted to be much smaller than in horizontal capillaries. These results suggest that, for particles circulating in an external field of volume forces (gravitation or magnetic), the strategy of using larger particles designed to marginate and adhere firmly to the vascular walls under flow could be more effective than that of using particles sufficiently small (d < 200 nm) to hopefully cross a discontinuous endothelium.

No MeSH data available.


Related in: MedlinePlus