PhD defense by Jaco Botha

The Department of Clinical Medicine, Aalborg University and Aalborg University Hospital are pleased to invite to PhD defense by M.Sc., Jaco Botha, who will defend the thesis entitled: HIGHLY SENSITIVE FLOW CYTOMETRY FOR THE CHARACTERISATION OF EXTRACELLULAR VESICLES: A study into analytical aspects, artefacts, and challenges that can influence the interpretation of results from clinical studies


11.01.2022 kl. 13.00 - 16.00


The PhD defense will take place

Tuesday January 11th, 2022
Time: 13:00-16:00,

Online via zoom: https://aaudk.zoom.us/j/62269079787



Professor Aase Handberg,
Department of Clinical Medicine,
Aalborg University

Assessment Committee

Associate Professor Pablo Pennisi,
Department of Health Science and Technology
Aalborg University, Denmark

Professor Victoria Weber
Department of Biomedical Research
Danube University Krems, Austria

Senior Scientist Jan Trige Rasmussen
Department of Molecular Biology and Genetics
Aarhus University, Denmark


About the PhD thesis

This PhD thesis is based on four studies, which aimed to investigate pre-analytical and analytical aspects of flow cytometry characterisation of extracellular vesicles (EVs), a heterogeneous group of biological nanoparticles with great diagnostic and therapeutic potential, which are released by all cells and readily present in all body fluids.

In study 1, we assessed the ability of three different flow cytometry platforms to resolve small particles in the EV size range from background, detect different EV phenotypes, and variability in quantifying different EV phenotypes in blood plasma.

In study 2, we determined the extent to which fluorescent antibody and protein label aggregates can be detected by highly sensitive flow cytometry and compared the extent to which high-speed centrifugation and filtration of reagents prior to staining reduce fluorescent aggregates.

In study 3, we optimised a labelling protocol for large lipoproteins including the very-low density lipoprotein and chylomicrons and investigated to which extent these nanoparticles confound on results from EV studies, where lipid-based methods are commonly used to define EVs.

In study 4, we present a systematic method for optimisation of analytical parameters, where the lower resolution limit is defined in standardised units, and how this metric can be used to define which settings are optimal for measuring dim signals from sub-micron particles such as EVs.

Collectively, these studies contribute to a growing body of literature, whose focus is on defining and overcoming pitfalls in EV research and standardisation of methodology and reporting. Specifically, several important pre-analytical and analytical issues related to flow cytometry characterisation of EVs are addressed that can influence result interpretation.


Department of Clinical Medicine


Online via Zoom

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