Related Experiment Video
Updated: Aug 9, 2025
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
Margination of 2D Platelet Microparticles in Blood
Jordan Thomas Lovegrove1, Radhika Raveendran1, Patrick Spicer2
1Centre for Advanced Macromolecular Design, School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia.
Abstract:
Margination describes the movement of particles toward the endothelial wall within blood vessels. While there have been several studies tracking the margination of spherical particles in blood, the behavior of anisotropic particle shapes is not well described. In this study 2D platelet particles which possess many attractive qualities for use as a drug delivery system, with their high surface area allowing for increased surface binding activity, were directly monitored and margination quantified. The margination propensity of 1 and 2 μm 2D platelet particles was contrasted to that of 2 μm spherical particles at apparent wall shear rates (WSRs) of 50, 100, and 200 s-1 by both directly tracking labeled particles using fluorescent microscopy as well as using small-angle X-ray scattering (SAXS). For fluorescence studies, margination was quantified using the margination parameter M, which describes the number of particles found closest to the walls of a microfluidic device, with an M-value of 0.2 indicating no margination. Increased margination was seen in 2D platelet particles when compared to spherical particles tested at all flow rates, with M-values of 0.39 and 0.31 seen for 1 and 2 μm 2D platelet particles, respectively, while 2 μm spherical particles had an M-value of 0.21. Similarly, margination was observed qualitatively using SAXS, with increased scattering seen for platelet particles near the microfluidic channel wall. For all particles, increased margination was seen at increasing shear rates.
Insights
Anisotropic 2D platelet particles show increased margination toward blood vessel walls compared to spherical particles. This enhanced margination, particularly at higher shear rates, suggests potential for improved drug delivery systems.
Area of Science:
- Biomedical Engineering
- Fluid Dynamics
- Materials Science
Background:
- Particle margination, movement towards vessel walls, is crucial for drug delivery.
- Behavior of anisotropic particles, like platelets, in blood flow is less understood than spherical particles.
- 2D platelet particles offer potential for drug delivery due to high surface area.
Purpose of the Study:
- To quantify and compare the margination of 2D platelet particles versus spherical particles.
- To investigate the effect of particle size and wall shear rate on margination.
- To evaluate 2D platelet particles as potential drug delivery systems.
Main Methods:
- Direct tracking of fluorescently labeled 1 and 2 μm 2D platelet particles and 2 μm spherical particles using fluorescent microscopy.
- Quantification of margination using the margination parameter (M).
- Qualitative assessment of margination using small-angle X-ray scattering (SAXS) at wall shear rates (WSRs) of 50, 100, and 200 s⁻¹.
Main Results:
- 2D platelet particles exhibited significantly higher margination than spherical particles across all tested WSRs.
- Margination parameter (M) values were 0.39 for 1 μm and 0.31 for 2 μm 2D platelets, versus 0.21 for 2 μm spheres.
- SAXS confirmed increased margination of platelet particles near the microfluidic channel wall.
- Margination increased for all particle types with increasing WSR.
Conclusions:
- Anisotropic 2D platelet particles demonstrate superior margination compared to spherical particles.
- The enhanced margination of platelet particles suggests their suitability for targeted drug delivery applications.
- Flow conditions, specifically higher shear rates, promote particle margination.
Related Concept Videos
01:18Structure and Function of Platelets
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
01:22Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...