EV core

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The first core facility for EV research in the world

The University of Helsinki EV core is a co-operated venture of the Faculty of Biological and Environmental Sciences (Viikki campus) and the Institute for Molecular Medicine Finland (FIMM) consisting of two laboratories dedicated to extracellular vesicle (EV) research. As an academic research service facility, the EV core provides infrastructure, state-of-the-art and emerging EV-technologies for research groups, hospitals, companies and authorities in the EV-field. The EV core facility provides EV isolation and characterization services and can offer sample preparation know-how and contacts to various downstream analyses in other UH core facilities based on optimized EV-protocols.

The EV-research group in Viikki focuses on understanding how EV-signals from various cellular sources e.g., platelets and cancer cells mediate and regulate cell behavior and crosstalk, and how EVs could be utilized in diagnostics and therapeutics. EV-research at FIMM focuses on liquid biopsy disease biomarkers taking advantage of the national sample collections, for example in the FinnDiane study, DIREVA study and Helsinki Biobank. Together, the EV core members have further developed the EV-know-how in a research consortium mixing academia and companies originally in the SalWe Ltd and now continuing in projects like EVE and Beat DKD. Currently, EV core is actively increasing the service portfolio, and working in collaboration with multiple companies and biobanks. The FIRI project is funded by Academy of Finland and specifically sets up equipment and workflows for single-particle analyses and high-throughput sample preparation for EV-RNA applications.  

The expertise of the EV core

• Sample material requirements (plasma, urine and cell culture media etc.), handling and storage 

• Sample preparation: EV isolation with the gold standard and new methods, EV-RNA isolation 

• EV-specified analysis methods: particle numbers and size, protein, nucleic acid, lipid, metabolite and EM analysis (some in collaboration with other core facilities within the University of Helsinki) 

• EV-characterization methods: marker analysis by Apogee flow cytometry and Exoview (coming in autumn 2021) 

• EV-specific data analysis/normalization 

The Apogee A50-Micro flow cytometry is specifically designed for measuring sub-micron biological particles. In contrast to conventional flow cytometers that have difficulties in detecting sub-micron particles, Apogee A50-Micro can measure biological particles down to about 150 nm diameter, thus providing research opportunities in the study of e.g:

  • extracellular vesicles (microvesicles, exosomes)
  • nanoparticles
  • platelets

Apogee’s light scatter and fluorescence detectors are routinely calibrated, which enables improved data-analysis and comparison of data between laboratories and instruments. With the calibrated Apogee A50-Micro one can:

  • Measure EV concentrations
  • Size EVs
  • Characterize EVs via fluorescent labeling (single- and double-marker analyses)
  • Quantitate fluorescence

Instrument in a nutshell

  • Three lasers: violet (405 nm), blue (488 nm) and red (638 nm)
  • Six fluorescent detectors: 405-green, 405-orange, 488-green, 488-orange, 488-red, and 638-red
  • Two light scatter detectors: 405-FSC and 405-SSC
  • Two sample formats: manual (1.5 ml tubes) and autosampler (96-well plate)
  • Minimum sample volume: 200 µl
  • Optimal particle concentration: 107-108/ml
  • File format: .fcs (data can be exported to excel format)


Minimum charge is 1 h, after which every starting ½ hour is charged. The minimum time includes two sets of control beads and the baseline buffer run. Running one sample takes typically 2-5 minutes followed by 1 minute flushing cycle. The washing steps after samples are stringent and take from 20 minutes to 1 hour, depending on the number and concentration of samples. 

Basic solutions and disposables are provided. In case the user is not providing fluorescently labelled probes please contact the EV core for possibility to use EV-unit’s probes for additional fee.

Apogee data

Nanoparticle tracking analysis (NTA) is a method used to quantify and determine the size distribution of nanoparticles ranging from 30 nm to 1 µm of diameter. The sample is injected to the measuring chamber and the sample particles are visualized using a laser beam. Particles pass through the beam path are seen as small points of light moving rapidly under Brownian motion, allowing information on particle properties to be obtained.

The Nanopartice Tracking Analysis provides characterization of:

  • extracellular vesicles including exosomes
  • microparticles
  • nanoparticles


Nanosight LM14C

  • Blue laser 405 nm, 60 mW
  • CMOS camera
  • Nanosight software v3.0
  • Minimum volume 500 µl
  • Optimal concentration of sample is around 5 x 108 particles/ml
  • Results are provided in PDF and excel files


Minimum charge is for 1 h, after which every starting ½ hour is charged. The minimum time includes the baseline buffer run. Running one sample takes typically 5-10 minutes and the analysis of the sample 5-10 minutes, during which the equipment is washed.

Basic solutions and disposables are provided. The used sample buffer should be filtrated with 0,1 µm filtration unit to prevent any external particles in the sample.

NTA data

Electron microscopy (EM) is one of the basic characterization techniques used to verify the success of EV isolation and to detect specific antigens such as EV marker proteins directly in situ. EM allows visualization and quantification of the morphology, size distribution and labelling of the EVs. It also gives information of the purity of EV preparations.

EM service of the EV Core provides characterization of EVs particularly in the size range of:

  • Exosomes
  • Microvesicles


EV Core FIMM provides EM and immuno-EM sample preparation using whole mount samples and negative staining protocol and, optionally, microscopy of the EV samples.

Basic solutions and disposables are provided. The suspension buffer of the EV sample should preferably be filtered with 0,1-0.2 µm filter to deplete any external particles in the sample.

EV core facility collaborates with the EM unit, Institute of Biotechnology, Viikki


All customers are oblicated to deliver prefilled project sheet together with a list of samples prior to EV Core services.


Head of the EV core Viikki, Docent Pia Siljander, pia.siljander|a|helsinki.fi, +358 (0) 504486373, +358 (0) 294159023                                                                  

Coordinator EV CoreViikki, Mari Palviainen, PhD, mari.palviainen|a|helsinki.fi, +358 (0) 2941 59031

EV Core Viikki, Ida Vänttinen, BSc, ida.vanttinen|a|helsinki.fi

Head of the EV core FIMM, Maija Puhka, PhD, maija.puhka|a|helsinki.fi, +358 (0) 400 826846, +358 (0) 2941 25879, EV Core FIMM