Plain-language summary
Small extracellular vesicles are candidates for inhaled drug delivery, but a vesicle that enters the airways has to cross the mucus layer and then the epithelial cell layer before it reaches the tissue underneath. This study asked whether adding phospholipids to the vesicle surface after secretion can tune that journey. The authors used vesicles carrying an eGFP-CD81 reporter and mixed them with either a zwitterionic lipid (DLPC) or a PEGylated lipid (DPA) at a range of lipid-to-vesicle ratios. Both treatments changed surface charge and colloidal stability while leaving vesicle size unchanged at the right ratios, although excess DPA caused clumping. In a mucin gel, lipid-modified vesicles diffused faster than unmodified ones, and DLPC at a 30,000 to 1 ratio gave the highest cumulative permeability with more diffusive particle motion. In a three-dimensional epithelial-endothelial co-culture, the same formulation reached the greatest permeability and basolateral accumulation. Fluorescent labelling showed that although all formulations entered apical cells, only DLPC-modified vesicles were detectable on the basolateral side. Neither lipid reduced cell viability or disturbed barrier morphology.
Key findings
- Small extracellular vesicles used for pulmonary delivery must cross two sequential barriers: airway mucus and the epithelium-endothelium interface.
- Post-secretory modification with a zwitterionic lipid (DLPC) or a PEGylated lipid (DPA) tuned surface charge and colloidal stability without changing vesicle size at optimised ratios.
- At a 30,000 to 1 lipid-to-vesicle ratio, DLPC gave the fastest mucus diffusion, the highest cumulative permeability and the greatest basolateral accumulation; DPA-modified vesicles tended to stay at the apical layer.
- Neither lipid affected cell viability or barrier morphology, and the authors position DPA for uses that need strong epithelial retention.
Why this matters for lung repair
For inhaled vesicle therapy this is a directly relevant formulation study: it quantifies how a simple lipid treatment changes transit through mucus and across the pulmonary epithelial barrier, and it identifies a lead lipid composition. The data come from reconstituted mucus and a cell co-culture, with no animal or clinical results, so it should be read as design guidance rather than evidence of therapeutic benefit.
Original abstract
Small extracellular vesicles (sEVs) are emerging as promising nanocarriers for non-invasive pulmonary drug delivery, yet their effectiveness is limited by sequential barriers imposed by airway mucus and the pulmonary epithelium-endothelium interface. Here, we investigated how post-secretory surface engineering with exogenous phospholipids modulates sEVs transport across lung-relevant barriers. eGFP-CD81 engineered sEVs were post-secretory modified at their surface composition using different lipid-to-vesicle ratios of either the zwitterionic lipid 1,2- Dilauroyl-sn-glycero-3-phosphocholine (DLPC) or the PEGylated lipid 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) -PEG(5000) - Azide (DPA). Both modifications enabled controlled tuning of surface charge and colloidal stability without altering vesicle size at optimized lipid-to-vesicle ratios, although excessive DPA induced aggregation. The physicochemical properties and transport behaviour of engineered sEVs were evaluated in a reconstituted mucin gel and a 3D pulmonary epithelial-endothelial co-culture model. In mucin-containing medium, lipid-engineered sEVs showed enhanced diffusion compared with unmodified vesicles, with DLPC at a 30,000:1 ratio providing the highest cumulative permeability, sustained apparent permeability coefficients, and more diffusive motion profiles, as confirmed by multiple particle tracking. In the 3D co-culture, the same modification achieved the greatest cumulative permeability and basolateral accumulation, indicating efficient transcellular passage, while DPA-functionalized vesicles displayed moderate permeability and predominant retention at the apical epithelial layer. Through fluorescently-labelling EVs, we confirmed that all formulations were internalized by apical cells, but only DLPC-engineered sEVs reached detectable levels in basolateral cells. Neither DLPC nor DPA affected cell viability or barrier morphology. Overall, our results identify DLPC at 30,000:1 as a lead formulation that balances mucus penetration and efficient crossing of the pulmonary barrier, while DPA is better suited for applications requiring strong epithelial engagement. Our findings highlight rational phospholipid engineering as a powerful approach to tailor sEVs-based nanomedicines for pulmonary delivery.
Frequently asked questions
What did this study find?
Small extracellular vesicles are candidates for inhaled drug delivery, but a vesicle that enters the airways has to cross the mucus layer and then the epithelial cell layer before it reaches the tissue underneath. This study asked whether adding phospholipids to the vesicle surface after secretion can tune that journey. The authors used vesicles carrying an eGFP-CD81 reporter and mixed them with either a zwitterionic lipid (DLPC) or a PEGylated lipid (DPA) at a range of lipid-to-vesicle ratios. Both treatments changed surface charge and colloidal stability while leaving vesicle size unchanged at the right ratios, although excess DPA caused clumping. In a mucin gel, lipid-modified vesicles diffused faster than unmodified ones, and DLPC at a 30,000 to 1 ratio gave the highest cumulative permeability with more diffusive particle motion. In a three-dimensional epithelial-endothelial co-culture, the same formulation reached the greatest permeability and basolateral accumulation. Fluorescent labelling showed that although all formulations entered apical cells, only DLPC-modified vesicles were detectable on the basolateral side. Neither lipid reduced cell viability or disturbed barrier morphology.
Was this tested in humans or in the laboratory?
This is delivery-science work, focused on how the vesicles behave when they are administered.
Where can I read the original paper?
The full text lives with the publisher: https://doi.org/10.1016/j.mtbio.2026.103637
Does this study prove that JuvGuard works?
No. This is an independent, peer-reviewed study on extracellular vesicles. JuvGuard references the published literature for education only. A single paper cannot establish that any product works, and nothing here is medical advice.
How to cite this paper
Sanchez Maria José, Leivar Pablo, Pinto Soraia, Almeida Helena, Artigues Margalida Esmeralda, Sarmento Bruno et al.. Balancing stability and cellular interaction in surface-engineered small extracellular vesicles for pulmonary delivery.. Materials today. Bio. 2026, 2026-09-12. DOI: 10.1016/j.mtbio.2026.103637
Source & verification
- Journal: Materials today. Bio
- Published: 12 September 2026
- DOI: 10.1016/j.mtbio.2026.103637
- PubMed ID: 42729759
- Indexed via: pubmed
- MeSH terms: —