Extracellular vesicles (EVs) are biological nanoparticles released by cells into body fluids, such as blood. Annually, thousands of studies claim that EVs are biomarkers for diseases. However, the results are often not reproducible for several reasons: (1) unknown detection limits and uncertainties thereof, (2) the smallest EVs cannot be detected, and (3) the rarest EVs are missed.

The last decade, we have developed a flow cytometry method to determine the concentration of EVs in blood plasma within known diameter and fluorescent intensity ranges. Although we achieved a high level of standardization, the complexity of the assay and technology as well as the thriving research field require continuous improvements of the used hardware (electronics, fluidics, optics). Hence, there are still many open questions, like:

• Which factors contribute most to the uncertainty of measured EV concentrations?
• How can we detect the smallest EVs in body fluids at a high throughput?
• What is the optimal balance between sensitivity and speed?
• Could optical improvements, like spectral flow cytometry or interferometric detection, push the limits further?

Any improvement can be directly applied to EV samples in clinical biobanks, such that an EV-based biomarker for diseases is within reach.

The main aim of this research is to improve the hardware (electronics, fluidics and optics) of a flow cytometer to realize an EV-based biomarker for diseases. This research requires hardware and software innovations and hence there is plenty of space for your own initiatives. The approach includes:

• Making the first uncertainty budget of EV concentration measurements with flow cytometry;
• Developing hardware and software solutions to improve the sensitivity and speed of a flow cytometer as well maximizing the information that can be retrieved from a single particle, for example by implementing spectral flow cytometry or interferometric detection. A flow cytometer at the optical bench is available and ready for optical modifications;
• Finding the optimum between sensitivity and speed in the context of rare EV detection.

We are looking for a candidate with a background in applied physics, biomedical engineering, or the like with a profound knowledge of and practical experience with optics.

• The candidate should be able to program and have affinity with electronics and fluidics;
• Wet lab experience might come in handy, but is not strictly required;
• Given the interdisciplinary character of our research, the candidate should be a team player that is eager to learn and able to explain complex matter to laymen;
• The complex problems require critical thinking as well as creative solutions. Although the candidate will be part of a team and supervision is done on weekly basis, an independent work attitude is required.

• A flying start to your career in research work in a metropolis with a diverse and open culture, and a multicultural society.
• Working with motivated colleagues from all corners of the world.
• You will start with a contract for one year (12 months) in accordance with the CAO UMC 2022-2023, with the possibility of extension for another three years (36 months).
• PhD students (Onderzoeker in Opleiding) are placed in scale 21, with a fulltime gross salary. The starting salary is € 2.901,- and increases to € 3.677,- in the fourth year.
• Effective of November 2023, a 4% salary increase will occur.
• In addition to a good basic salary, you will receive, among other things, 8.3% year-end bonus and 8% vacation allowance. Calculate your net salary here.
• Pension via BeFrank
• Reimbursement of 75% of your public transport costs. Would you rather travel by bike? Then we have a good bicycle scheme.
• An active staff association and the Young Amsterdam UMC association, both of which organize fun (sports) activities and events.

Amsterdam UMC

This project is kindly funded by Amsterdam UMC and will run in parallel with the NWO VIDI program “Count disease-related extracellular vesicles 1000-fold faster”, were currently 2 PhD students, a Postdoc researcher and the principle investigator are working on: Research into technologies for earlier diagnosis of disease.

Research will be done at the Department of Biomedical Engineering & Physics and the Laboratory of Clinical Chemistry, which collaborate under the name Amsterdam Vesicle Center and currently has 17 group members. We have strong international collaborations in science and industry.