How Are Exosomes Produced and Processed?

Exosomes and other extracellular vesicles don't all come from the same source—and they aren't all obtained using the same process.

Some extracellular vesicles are collected from cells grown in culture. Others can be isolated directly from biological fluids, where extracellular vesicles are naturally present.

That distinction is important because the source material determines what happens at the beginning of the production process.

For example, a cell-culture-derived EV preparation may begin with growing cells and collecting the surrounding conditioned medium.

An amniotic-fluid-derived EV preparation starts differently: the extracellular vesicles are already present within the collected amniotic fluid.

From there, the material can be processed, purified and characterized to produce an extracellular-vesicle preparation.

Start With the Source

Extracellular vesicles are membrane-bound particles naturally released by cells.

As explained in What Are Exosomes? A Beginner's Guide, these particles can carry proteins, lipids, nucleic acids and other biological material associated with their cells of origin.

EVs can be collected from several types of source material.

Two important examples are:

Neither starting point alone tells you everything about the resulting preparation.

Source material, collection procedures, processing, purification, characterization and quality controls all provide additional information.

Extracellular Vesicles Are Naturally Present in Amniotic Fluid

Amniotic fluid is one biological fluid known to contain extracellular vesicles.

Researchers have isolated and characterized EVs directly from human amniotic fluid using methods including particle analysis, electron microscopy and protein-marker characterization.

This is different from isolating cells from amniotic fluid, growing those cells in culture, and later collecting the extracellular vesicles released by those cultured cells.

Both approaches appear in scientific research, but they aren't the same process.

This distinction also reinforces something discussed in Exosomes vs. Extracellular Vesicles: What's the Difference?: understanding where a vesicle population came from is important when describing and characterizing it.

How Cell-Culture-Derived EVs Are Obtained

In cell-culture systems, selected cells are maintained under controlled conditions.

As those cells remain in culture, they naturally release extracellular vesicles into the surrounding liquid, commonly called cell culture-conditioned medium.

The conditioned medium can then be collected and processed to separate and concentrate the EV-containing fraction.

Culture conditions can influence the resulting material, which is why researchers document factors such as cell source, culture medium and collection conditions.

The general process looks something like:

But that's only one way of obtaining extracellular vesicles.

How Biofluid-Derived EVs Are Obtained

Biological fluids can already contain extracellular vesicles released naturally by cells within the body.

EVs have been studied in biofluids including blood, urine and amniotic fluid. Researchers can therefore begin with the biological fluid itself rather than first establishing a cell culture.

The general pathway becomes:

Amniotic fluid is particularly interesting in this context because researchers have demonstrated that extracellular vesicles can be isolated directly from it.

Importantly, amniotic fluid is a complex biological material. Published methods describe multiple processing and cleanup steps when isolating and characterizing EVs from it.

How HydroKarma's Process Begins

HydroKarma uses the biofluid-derived pathway rather than growing cells for the purpose of collecting extracellular vesicles from cell-culture-conditioned media.

According to information provided by KWEHEALTH/HydroKarma and its product documentation, the starting material is clinical-grade human amniotic fluid obtained from pre-screened donors undergoing planned cesarean deliveries.

The process begins before the amniotic fluid reaches the manufacturing facility.

Specific donor criteria are used to determine donor suitability, and the collection is performed by a trained and authorized tissue-acquisition organization.

The collected amniotic fluid is then delivered to the manufacturer within approximately 24 hours of collection.

Donor Screening and Qualification

When working with human-derived biological material, understanding the source begins with donor qualification.

According to KWEHEALTH's product documentation, donor medical records are screened for information related to risk factors for relevant communicable diseases.

The documented screening process includes:

• a communicable-disease serology panel
• medical-history review and interview
• physical examination
• behavioral risk assessment
• review of other information or records relevant to donor suitability

These procedures occur as part of the manufacturer's source-material and quality process.

Receipt, Quarantine and Testing

When the collected amniotic fluid reaches KWEHEALTH, the material is placed into quarantine.

Samples are sent for testing for viruses and relevant communicable diseases.

The material remains quarantined until the required testing has been completed and it has been cleared to proceed according to the manufacturer's quality procedures.

That creates an important sequence before processing even begins:

This illustrates why understanding an extracellular-vesicle preparation involves more than simply looking at the final particle count.

Processing and Purification

Once the source material has cleared the required testing, HydroKarma reports that the amniotic fluid proceeds through processing and purification.

Amniotic fluid contains much more than extracellular vesicles.

Published research describing amniotic-fluid EV isolation notes that the starting fluid contains proteins, cells and other components that require multiple processing steps when researchers want to isolate and characterize EV populations.

Processing and purification therefore serve an important purpose: separating and refining the material of interest from a complex biological starting material.

The precise methods used can vary considerably.

How EV Separation and Purification Can Be Performed

Across the broader EV field, scientists use several approaches for separating or concentrating extracellular vesicles.

Examples include:

• differential centrifugation and ultracentrifugation
• filtration
• tangential-flow filtration
• size-exclusion chromatography
• affinity-based approaches
• combinations of multiple techniques

Researchers studying human amniotic-fluid-derived EVs have likewise described combinations of separation, filtration and characterization methods.

However, these examples describe methods used across EV research.

They should not be interpreted as a description of HydroKarma's proprietary purification process unless KWEHEALTH/HydroKarma specifically identifies a method as part of its manufacturing process.

That's an important distinction.

Separation, Purification and Characterization Aren't the Same Thing

These terms are sometimes used together, but they describe different parts of the process.

Separation and purification concern obtaining and refining the desired material from the starting sample.

Concentration concerns increasing the amount of the material of interest within a given volume.

Characterization concerns measuring and examining properties of the resulting preparation.

Characterization may involve measurements such as:

• particle concentration
• particle-size distribution
• morphology
• EV-associated proteins or markers
• additional biochemical or physical properties

As we discuss in Understanding Exosome Concentration and Particle Count, particle count is useful information, but it doesn't tell you everything about an EV preparation.

Multiple measurements can provide a more complete picture.

Characterizing Amniotic-Fluid-Derived EVs

Researchers have used several complementary methods to characterize extracellular vesicles isolated from human amniotic fluid.

For example, Ebert and Rai described isolation of EVs from amniotic fluid followed by validation using protein-marker analysis and transmission electron microscopy.

Sheller-Miller and Menon likewise described isolation and characterization approaches examining particle size, morphology and protein markers.

This illustrates an important principle:

From Characterization to Vialing

According to the manufacturing information provided to Express Biologics, after HydroKarma's amniotic-fluid-derived material has been processed and purified, the resulting preparation is characterized and vialed.

KWEHEALTH's product documentation states that manufacturing occurs using aseptic techniques within an ISO-certified controlled environment designed to limit contamination and cross-contamination.

The documentation also describes quality-assurance testing and environmental monitoring associated with finished lots, including aerobic, anaerobic and sterility testing.

Once processing, characterization, vialing and required quality procedures are complete, the finished product can be released for shipment.

The HydroKarma Process at a Glance

Based on the manufacturing information currently provided by KWEHEALTH/HydroKarma, the high-level workflow can be understood as:

• 1. Donor criteria and screening
• 2. Planned cesarean delivery
• 3. Collection of clinical-grade amniotic fluid by an authorized tissue-acquisition organization
• 4. Delivery to the manufacturer within approximately 24 hours
• 5. Receipt and quarantine
• 6. Communicable-disease testing
• 7. Release of qualified material for processing
• 8. Processing and purification
• 9. Extracellular-vesicle characterization
• 10. Vialing
• 11. Quality-assurance testing and lot documentation
• 12. Release for shipment

This high-level description intentionally doesn't speculate about proprietary processing steps that haven't been publicly documented.

Why Source and Processing Matter

Two products can display similar particle counts while having very different histories.

They may begin with different source materials.

They may use different collection procedures.

They may undergo different separation and purification processes.

They may use different characterization methods.

And they may be manufactured under different quality systems.

That's why understanding extracellular-vesicle products requires looking beyond a single number.

The useful questions become:

• Where did the material come from?
• How was the source qualified?
• How was it collected and handled?
• How was the material processed and purified?
• How was the resulting EV preparation characterized?
• What batch-specific testing and documentation are available?

Those questions provide a much more complete picture of how an extracellular-vesicle preparation reached its finished form.

The Bottom Line

There isn't one universal answer to “How are exosomes produced?”

Some extracellular-vesicle preparations originate from cultured cells and conditioned media.

Others originate directly from biological fluids that naturally contain extracellular vesicles, including human amniotic fluid.

HydroKarma's process belongs to the second category.

Its products begin with clinical-grade human amniotic fluid obtained from pre-screened donors undergoing planned cesarean deliveries. The material is collected by an authorized tissue-acquisition organization, transported to the manufacturer, quarantined and tested before being released for processing. It is subsequently processed, purified, characterized and vialed under the manufacturer's documented quality procedures.

Understanding that pathway helps put the finished particle count, characterization results and Certificate of Analysis into context.