Exosomes are bought on trust more than on spec sheets, because the field has no single pharmacopoeial standard yet. The best protection is to ask the questions below before you order — and to expect specific, documented answers.
1. What is the source, and can it be traced?
Plant, stem-cell, milk and microbial vesicles behave differently, so the source decides cargo, supply risk and the claims you can make. A supplier should name the species or tissue, the plant part or cell line, and the harvest or culture batch. For human-derived material, ask about donor consent and screening.
2. How were the vesicles isolated?
Ultracentrifugation, size-exclusion chromatography, tangential-flow filtration and polymer precipitation give different purity and yield. None is wrong, but the method should be stated, because it explains what else may be in the vial — such as protein aggregates or co-isolated polymer.
3. Is size reported with more than one method?
Nanoparticle tracking and dynamic light scattering give a size distribution; electron microscopy shows the vesicles directly. A median in the 30–200 nm range, confirmed by microscopy, is the expected picture for exosomes. A single method alone cannot prove identity — a point made throughout the MISEV guidelines.
4. How is concentration defined?
Particles per millilitre is the number that matters for dosing. If concentration is inferred from protein, the conversion should be written on the certificate. Ask for the minimum guaranteed concentration, not a typical value.
5. Does the certificate show methods, not just numbers?
A line reading “protein: 2.4 µg/mL” is far less useful than the same line with the assay named. Method-tagged results are what make one batch comparable to the next.
6. What safety testing is done on every batch?
- Sterility and microbial load (aerobic count, yeast and mould, specified organisms)
- Endotoxin and, for cell-culture sources, mycoplasma
- Heavy metals, and aflatoxin or pesticide screening for botanicals
7. Is there stability data, and at what temperature?
Vesicles are sensitive to storage. Ask for real-time stability results at the temperature you will actually use, and for the shelf life that data supports — not an extrapolation.
8. What documents come with the product?
At minimum a certificate of analysis and a safety data sheet for each batch. Larger programmes should also ask for a technical dossier covering characterisation and handling.
9. What are the minimum order and lead time?
Minimum orders are usually set in total particles, not volume. Work out the particles you need first, then check the supplier can meet it without changing concentration between lots.
10. Is the grade and intended use stated plainly?
Research-grade and cosmetic-grade materials are not clinical-grade. A trustworthy supplier says which grade is on offer and avoids implying approval or treatment benefit that has not been established.
EXOMIE supplies 48 characterised exosomes and bioactives with a certificate of analysis and safety data sheet for each batch. See bulk supply, how to read a certificate of analysis, or send us your specification.