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Updated: May 28, 2026
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
Validation of flow cytometric detection of platelet microparticles and liposomes by atomic force microscopy
H S Leong1, T J Podor, B Manocha
1The James Hogg Research Centre, St Paul's Hospital, Vancouver, BC. hon.leong@lhsc.on.ca
Background:
Platelet microparticles (PMPs) are a promising prognostic marker for thrombotic disorders because of their release during platelet activation. The use of flow cytometry for the enumeration of PMPs in plasma has generated controversy due to their size, which is below the stated detection limits of conventional flow cytometry instruments. The potential impact of this is an underestimation of PMP counts.
Objectives/Methods:
To address this possibility, we used a combination of fluorescence-activated cell sorting (FACS) and atomic force microscopy (AFM) to determine the size distribution of PMPs present in plasma from acute myocardial infarction (AMI) patients and normal volunteers, and PMPs generated by expired platelet concentrates and washed platelets treated with agonists such as thrombin and calcium ionophore (A23187).
Results:
According to AFM image analysis, there was no statistically significant difference in height or volume distributions in PMPs from thrombin-activated, calcium ionophore-activated, expired platelet concentrates and plasma from healthy volunteers and AMI patients. Based on volume, expired platelets released the greatest proportion of exosomes (< 1.0 × 10(-22) L(3) in volume) in relation to the entire PMP population (29.7%) and the smallest proportion of exosomes was observed in AMI patient plasma (1.8%). Moreover, AFM imaging revealed that PMPs from expired platelets exhibited smooth surfaces compared with other PMP types but this was not statistically significant.
Conclusions:
We confirm that flow cytometry is capable of analyzing PMPs from plasma by using AFM to perform nanoscale measurements of individual PMP events isolated by FACS. This method also provided the first quantitative nanoscale images of PMP ultrastructure.
Insights
Atomic force microscopy (AFM) and fluorescence-activated cell sorting (FACS) confirm flow cytometry can analyze platelet microparticles (PMPs). This technique provides nanoscale measurements and ultrastructure images, addressing underestimation concerns in thrombotic disorder diagnostics.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Hematology
Background:
- Platelet microparticles (PMPs) are crucial prognostic markers for thrombotic disorders.
- Conventional flow cytometry may underestimate PMP counts due to their small size.
- Accurate PMP enumeration is vital for diagnosing and monitoring thrombotic conditions.
Purpose of the Study:
- To determine the size distribution of PMPs using a combination of FACS and AFM.
- To compare PMPs from acute myocardial infarction (AMI) patients, healthy volunteers, and aged platelet concentrates.
- To validate flow cytometry's capability in analyzing PMPs through nanoscale measurements.
Main Methods:
- Utilized fluorescence-activated cell sorting (FACS) for PMP isolation.
- Employed atomic force microscopy (AFM) for nanoscale size distribution and ultrastructure analysis.
- Analyzed PMPs from AMI patient plasma, healthy volunteer plasma, expired platelet concentrates, and agonist-stimulated washed platelets.
Main Results:
- No significant differences in PMP height or volume distributions were found across all sample types.
- Expired platelets released the highest proportion of exosomes (29.7%) by volume.
- AFM revealed smoother surfaces on PMPs from expired platelets, though not statistically significant.
Conclusions:
- Flow cytometry can effectively analyze plasma PMPs when coupled with AFM for nanoscale validation.
- This combined approach enables accurate PMP quantification and provides detailed ultrastructural insights.
- The findings support the use of advanced imaging techniques for reliable PMP analysis in clinical diagnostics.
