.png)
Why Particle Size Matters: How Smaller Exosomes May Improve Skin Penetration | P198 ExoHealer
- The Athena Team
- Jun 19
- 4 min read
Updated: 4 days ago
When clinics compare exosome skin boosters, the conversation usually starts and ends with growth factor counts or stem cell origin claims. One of the most clinically meaningful — and most overlooked — specifications is something far more measurable: particle size. It's also one of the reasons P198 ExoHealer™ is formulated the way it is.
A growth factor figure printed on a spec sheet tells you almost nothing on its own. What matters is whether the particles carrying those growth factors are small enough, numerous enough, and verifiably exosomal to begin with. This article walks through what particle size data actually measures, how it's generated, and why P198 ExoHealer's umbilical cord stem cell-derived exosomes were built around exactly this benchmark.
What Particle Size Actually Measures
Exosomes are nanoscale extracellular vesicles, typically somewhere between 30 and 250 nanometres in diameter. Because the skin's outer layers are a selective barrier, the physical size of a particle is directly relevant to how — and whether — it can interact with deeper skin structures.
In published research, particle size and concentration are most commonly measured using Nanoparticle Tracking Analysis (NTA, e.g. NanoSight systems), which reports both the mean diameter and the number of particles per millilitre. Reputable studies pair this with transmission electron microscopy (to confirm vesicle morphology) and surface marker testing — such as detecting the protein CD81 via ELISA — to confirm the particles are genuine exosomes rather than general cellular debris.
"A growth factor count means little if the particles carrying it are too large, too few, or were never confirmed to be exosomes in the first place."
Comparing Exosome Sources Side-by-Side
A peer-reviewed characterisation study published in Biochemical and Biophysical Research Communications — part of the published research underpinning the umbilical cord stem cell exosome technology used in P198 ExoHealer's FILCORE solution — directly compared exosomes isolated from three different conditioned media sources: umbilical cord stem cells (USC-CM), adipose-derived mesenchymal stem cells (AD-MSC-CM), and human dermal fibroblasts (HDF-CM).
Of the three sources studied, exosomes derived from umbilical cord stem cell conditioned media were the smallest, the most numerous per millilitre, and showed the narrowest size distribution — a consistency the study's authors linked to easier standardisation, an important factor for manufacturing reliability. This is the same source profile behind P198 ExoHealer's FILCORE solution: it's formulated specifically around umbilical cord stem cell-derived exosomes rather than adipose- or fibroblast-derived alternatives, on the basis of this particle data.
Why Smaller Particle Size May Mean Better Skin Permeation | P198 Exohealer
Smaller nanoparticles generally have an easier path through the intercellular lipid channels of the stratum corneum than larger ones — a principle well established in the broader dermal nanoparticle penetration literature. The same study tested this directly: fluorescently labelled umbilical cord stem cell exosomes were applied to human abdominal skin explants and tracked using fluorescence microscopy at 0, 3, and 18 hours, with visible signal observed migrating into the epidermis within that window.
It's worth being precise about what this does and doesn't show: this was an ex vivo skin explant model under laboratory conditions, not an in-clinic outcome study. It demonstrates penetration potential rather than guaranteeing a specific clinical result for every patient.
Downstream Effects Observed in Treated Fibroblasts
In the same body of research, human dermal fibroblasts treated with umbilical cord stem cell exosomes showed increased Collagen I and elastin gene expression, alongside decreased expression of MMP-1 (an enzyme associated with collagen breakdown). Treated fibroblasts also migrated faster in scratch-assay testing compared with untreated controls.
These are cellular and molecular findings consistent with mechanisms relevant to skin regeneration — they describe what was observed in the lab, not a guaranteed clinical outcome in every patient. They're also the underlying rationale Athena BioMed points to when discussing how P198 ExoHealer's exosome source was selected.
What to Ask a Supplier Before You Stock a Product
Request NTA/NanoSight data — ask for the full size distribution curve, not just a single average figure.
Ask for particle concentration per mL, not only a growth factor count — the two numbers tell you different things.
Confirm exosome identity testing — ask whether markers such as CD81, CD63 or CD9 were used to verify the particles are genuine exosomes.
Check the source of the data — peer-reviewed or independently verified data carries more weight than internal-only reports.
The Takeaway for Clinics
Particle size isn't the whole story — purity, concentration, growth factor profile, and your own clinical protocol all matter too. But unlike most marketing claims, particle size is directly measurable, comparable across products, and worth requesting before any exosome line earns a place on your treatment menu. It's also why Athena BioMed leads with this data when clinics ask what sets P198 ExoHealer™ apart: the umbilical cord stem cell exosome source at its core was selected on the strength of exactly the particle-size and concentration profile outlined above.
Findings described are drawn from in vitro and ex vivo laboratory research. They describe observed laboratory results and are not a guarantee of individual clinical outcomes, which may vary by patient and protocol. This article is intended for healthcare professional education and does not replace independent clinical judgement.
Kim, Y.-J. et al. (2017). Biochemical and Biophysical Research Communications, 493, 1102–1108.
