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High-Yield, Magnetic Harvesting of Extracellular Outer-Membrane Vesicles from Escherichia coli
Rui Shi1,2, Ziliang Dong1, Chongqing Ma1
1Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren'ai Rd, Suzhou, Jiangsu, 215123, P. R. China.
Abstract:
Extracellular outer-membrane vesicles (OMVs) are attractive for use as drug nanocarriers, because of their high biocompatibility and ability to enter cells. However, widespread use is hampered by low yields. Here, a high-yield method for magnetic harvesting of OMVs from Escherichia coli is described. To this end, E. coli are grown in the presence of magnetic iron-oxide nanoparticles (MNPs). Uptake of MNPs by E. coli is low and does not increase secretion of OMVs. Uptake of MNPs can be enhanced through PEGylation of MNPs. E. coli growth in the presence of PEGylated MNPs increases bacterial MNP-uptake and OMV-secretion, accompanied by upregulation of genes involved in OMV-secretion. OMVs containing MNPs can be magnetically harvested at 60-fold higher yields than achieved by ultracentrifugation. Functionally, magnetically-harvested OMVs and OMVs harvested by ultracentrifugation are both taken-up in similar numbers by bacteria. Uniquely, in an applied magnetic field, magnetically-harvested OMVs with MNPs accumulate over the entire depth of an infectious biofilm. OMVs harvested by ultracentrifugation without MNPs only accumulate near the biofilm surface. In conclusion, PEGylation of MNPs is essential for their uptake in E. coli and yields magnetic OMVs allowing high-yield magnetic-harvesting. Moreover, magnetic OMVs can be magnetically targeted to a cargo delivery site in the human body.
Insights
Researchers developed a high-yield method for magnetic harvesting of outer-membrane vesicles (OMVs) from Escherichia coli using PEGylated magnetic nanoparticles (MNPs). This technique significantly increases OMV yield and enables targeted delivery, overcoming previous limitations for nanocarrier applications.
Area of Science:
- Biotechnology
- Nanotechnology
- Microbiology
Background:
- Extracellular outer-membrane vesicles (OMVs) show promise as biocompatible drug nanocarriers due to cellular entry capabilities.
- Low yield during OMV isolation currently limits their widespread application in nanomedicine.
Purpose of the Study:
- To develop a high-yield method for harvesting OMVs from Escherichia coli using magnetic nanoparticles (MNPs).
- To investigate the role of PEGylation in enhancing MNP uptake and OMV secretion.
- To evaluate the efficacy of magnetically harvested OMVs for targeted delivery.
Main Methods:
- Escherichia coli were cultured with magnetic iron-oxide nanoparticles (MNPs), with enhanced uptake achieved via PEGylation.
- Gene expression related to OMV secretion was analyzed following MNP incubation.
- OMVs containing MNPs were magnetically harvested, and their yield and cellular uptake were compared to ultracentrifugation methods.
- Magnetic targeting of OMVs within bacterial biofilms was assessed.
Main Results:
- PEGylation of MNPs was essential for enhanced uptake by E. coli and increased OMV secretion.
- Magnetic harvesting yielded OMVs at 60-fold higher rates compared to ultracentrifugation.
- Magnetically harvested OMVs demonstrated efficient uptake by bacteria and magnetic accumulation within biofilms.
- Targeted accumulation of magnetic OMVs within biofilms was observed in an applied magnetic field.
Conclusions:
- PEGylated MNPs facilitate high-yield magnetic harvesting of OMVs from E. coli.
- This method significantly improves OMV yield and enables magnetically targeted delivery for potential therapeutic applications.
