A stem cell is a living cell. An exosome is not a cell at all.
What an exosome actually is
Cells communicate. One of the ways they do it is by releasing extremely small membrane-wrapped packages containing proteins, genetic material and other molecules. Exosomes are one class of those packages. Think of a cell as a person and an exosome as a sealed envelope that person sends out.
- Living cells.
- Can divide and make more of themselves.
- Respond to their surroundings over time.
- Have strict living-cell handling requirements.
- Not living cells — cell-derived particles.
- Cannot divide or replicate.
- Carry a payload of molecules; do not respond independently.
- Have their own handling and characterisation challenges.
Why the confusion happens
Because exosomes are often derived from cell cultures, marketing language sometimes slides between the two as if they were the same thing. They are not, and their regulatory treatment is not the same either.
Where the science stands
Exosome research is genuinely active and genuinely interesting — as a way to understand how cells signal to one another, and as a possible route for delivering molecules. That is a research frontier. It is not the same as an established treatment, and it should not be described as one.