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Platelet reactions to modified surfaces under dynamic conditions.
N P Rhodes1, A P Shortland, A Rattray
1Department of Clinical Engineering, Liverpool University, Duncan Building, Daulby Street, Liverpool L693GA, UK. npr@liv.ac.uk
Journal of Materials Science. Materials in Medicine
|September 7, 2004
Summary
Surface type influences blood reactions, affecting platelet aggregation and microparticle formation. Poly(methyl methacrylate) (PMMA) generated larger platelet aggregates, while red blood cell interactions varied with shear rate, impacting microparticle stability.
Area of Science:
- Biomaterials Science
- Hematology
- Surface Chemistry
Background:
- Platelet reactions to surfaces are critical in thrombosis and biomaterial interactions.
- Understanding how different surfaces and shear rates affect platelet behavior in whole blood is essential for developing biocompatible materials.
Purpose of the Study:
- To investigate the influence of various surfaces (steel, PMMA, PEO-modified PMMA) on platelet reactions in whole blood under different laminar flow shear rates.
- To quantify microparticle generation and aggregate formation (platelet-platelet, platelet-red blood cell, red blood cell-microparticle) and assess aggregate size.
Main Methods:
- Whole blood in a cone and plate viscometer exposed to steel, PMMA, and PEO-modified PMMA at 500 s(-1) and 4000 s(-1) shear rates.
- Flow cytometry analysis of fixed and stained blood samples using anti-CD41 antibody.
- Quantification of microparticle generation, aggregate formation, and platelet-platelet aggregate size.
Main Results:
- Platelet aggregation percentage and microparticle numbers were independent of surface type across shear rates.
- PMMA surfaces induced the largest platelet-platelet aggregates at both low and high shear rates.
- Red blood cell-platelet aggregate numbers decreased with increasing shear rate, while red blood cell-microparticle aggregates increased.
Conclusions:
- Surface properties significantly influence the composition and size of blood cell aggregates, particularly platelet-rich aggregates.
- Variations in aggregate formation and microparticle-red blood cell association may explain surface-induced thrombotic events.
- Microparticle association with red blood cells at high shear rates may prevent their loss from circulation.