HOLTRA

A brief guide to studying extracellular vesicle function in the context of metabolism Nature Metabolism - Extracellular vesicles (EVs) are now recognized as powerful modulators of metabolism, and thus the new field of EV-mediated metabolic regulation is growing exponentially. Here,...

Clair Crewe et al. offer a roadmap for studying extracellular vesicles (EVs), emphasizing plasma preparation, lipoprotein clearance, accurate particle dosing, and uptake validation to ensure reproducible results. @natmetabolism.nature.com doi.org/10.1038/s422... 🧪

DAISY nanoparticle tracking analysis is a powerful method for refractive index determination of nanoparticles!
learn more here: www.holtra.tech

Or between extracellular vesicles and lipoproteins!

This means that you can easily distinguish between protein aggregates and non-protein contaminants..

Put simply, refractive index measurements allow you to differentiate between populations of particles within your sample more effectively

Why should you consider adding refractive index measurements to your regular nanoparticle analysis?

Exosome tethering requires tetherin homodimerisation Exosomes are small extracellular vesicles that originate as intraluminal vesicles (ILVs) within multivesicular bodies (MVBs). Upon fusion of MVBs with the plasma membrane, ILVs are released into the e...

Exosome tethering requires tetherin homodimerisation www.biorxiv.org/content/10.1...

In summary, holographic microscopy offers label free, single shot, high resolution, high frame rate, 3D imaging! It sounds almost too good to be true, and that is why we are so convinced of it’s potential and excited to be developing microscopes around this technology!

For holographic microscopy, instead of physically illuminating the interference patterns to reveal the hologram, the hologram is reconstructed computationally. With rapid advances in processing power for these kinds of tasks, the potential of holographic microscopy is only growing!

This means that from a single light exposure a hologram captures a 3D representation of the object! The images of the mouse below are produced by viewing the same hologram from different angles!

To create a hologram, the light coming from the object is merged with another beam, creating interference pattern between the two beams. When the object is removed and the interference pattern illuminated, light is diffracted and a 3D image of the original object appears.

When light from an illuminated object is focussed and captured by a camera a 2D image is recorded. A hologram however is a 3D representation of the object of interest and is recorded differently. Relying on interference patterns similar to those seen between waves on water.

Firstly, what is a hologram?
holograms, like the Visa dove below, are very familiar. but what are they? Much like a recording of a sound, e.g. music, a hologram is a 3D “recording” of an illuminated object that can be replayed, even once the object is removed. But how are they created?

What is holographic microscopy?
And why are we so excited about it’s scientific potential?

Size is a key descriptor of extracellular vesicles #EV. In samples containing contaminating particles with an overlapping size distribution, size alone is insufficient. Measuring refractive index at the individual particle level enables differentiation of extracellular vesicles and lipoproteins.

For this study DAISY was used to monitor the purity and consistency of cell culture-derived exosome preparations. Check out our application not on DAISY for extracellular vesicles to learn more.
www.holtra.tech/en/applicati...

🧬Pre-print alert🧬 | James Edgar 🧬Pre-print alert🧬 In our latest manuscript, we’ve uncovered the molecular mechanism of exosome tethering. Using a mix of biochemical and imaging approaches, we tested different tetherin mutants to see...

Excited to share this pre-print from our collaborators, the Edgar lab, at the University of Cambridge, UK
www.linkedin.com/posts/james-...

Get in touch with us if you want to see for yourself how DAISY can revolutionise your nanoparticle analysis!
www.holtra.tech

To measure phase shift, DAISY employs digital holographic microscopy (DHM). DHM separates phase and intensity information to generate a 3D image of the light scattered by each particle from a single exposure.

Alongside size, DAISY measures the refractive index of each particle. It does this by directly measuring the phase shift of light passing through the particles. Denser materials give higher phase shift which means that, uniquely, DAISY can differentiate particles based on their composition!

Nanoparticle tracking analysis (NTA) records particles diffusing in solution. The smaller the particle the faster the diffusion. This is how NTA assigns a size.

What is DAISY?
DAISY is next generation nanoparticle tracking analysis!

MOVE2025

We will also be presenting at the European National Societies of Extracellular Vesicles MOVE symposium in Tartu, Estonia Oct 7th to 9th:
move2025.ee
See you there!

It is shaping up be a busy autumn! HOLTRA are excited to be presenting our technology at the European Colloid and Interface Society meeting in Bristol, UK. Sept. 7th to 12th
www.ecis-web.eu/about-us/eci...

DAISY can see inside your liposomes and lipid nanoparticle preparations to reveal internal structure!
Read more here:
www.holtra.tech/en/applicati...

DAISY nanoparticle tracking in action!
sample is 415 nm silica beads

Do you want to easily identify and quantify contaminants and aggregates in your extracellular vesicle samples?
Take a look at our EV application note to find out how DAISY can improve your EV analysis:
www.holtra.tech/en/applicati...

Check out our updated website for an overview of our technology and real-world applications in nanoparticle analysis:
www.holtra.tech