The human body is composed of tens of trillions of cells. To maintain normal operations, these cells must constantly exchange information and coordinate their work. In addition to transmitting signals through hormones and neurotransmitters, scientists have discovered that cells also release extremely tiny vesicle structures that act as messengers between cells. These vesicles can carry various biomolecular messages, such as proteins, lipids, and RNA nucleic acids, delivering this information to other cells. Among these, exosomes are currently the most widely researched class of extracellular vesicles.

Not All Nanoparticles are Exosomes

Being "nanometer-sized" is merely one of the basic characteristics of exosomes; it does not mean that all nanoparticles are exosomes. In fact, many different types of nanoscale particles exist in nature and living organisms—such as lipoproteins, protein aggregates, and other types of extracellular vesicles. While their sizes may be similar to exosomes, their functions can be vastly different.

Therefore, particle size analysis serves only as the preliminary threshold for exosome identification, not the final answer.

How to Confirm the True Presence of Exosomes?

The verification of exosomes must concurrently satisfy the following three types of evidence:

• Particle Size: The "size" of an exosome is its most fundamental identification metric, with a diameter of approximately 30–200 nm.
• Exosome Biomarker Proteins: The detection of at least 2–3 typical exosomal protein markers (such as CD9, CD63, TSG101, etc.) serves as the core evidence of its biological identity.
• Morphological Confirmation: Observation under a Transmission Electron Microscope (TEM) must reveal intact, circular, hollow lipid bilayer vesicles.

Only through a complete validation process can a substance truly align with the scientific definition of exosomes recognized by the international research community.

From cells to organs, the operation of life relies on the non-stop exchange of information. The discovery of exosomes not only allows us to deeply understand the mysteries of how life functions, but also opens up new research directions in biotechnology. However, quality standards, source management, and scientific verification will also become critical keys to future market development.