Covalent coupling of functionalized outer membrane vesicles (OMVs) to gold nanoparticles

Area of Science:

• Biotechnology
• Nanotechnology
• Materials Science

Background:

• Outer membrane vesicles (OMVs) are increasingly utilized for drug delivery and vaccine development.
• Encapsulating nanoparticles within OMVs offers enhanced therapeutic potential.
• Current methods for OMV-NP functionalization require optimization for efficiency and specificity.

Purpose of the Study:

• To develop novel outer membrane vesicle-functionalized nanoparticles (OMV-NPs) by encapsulating gold nanoparticles (AuNPs) using bioorthogonal click chemistry.
• To establish a simplified and efficient method for OMV-NP preparation.
• To demonstrate the potential of OMV-NPs for targeted drug delivery applications, specifically in cancer therapy.

Main Methods:

• Outer membrane protein A (OmpA) within OMVs was modified with p-azidophenylalanine to introduce azide groups.
• Alkyne-functionalized AuNPs were covalently coupled to the azide-modified OmpA via click reaction.
• A low-speed centrifugation method was optimized for OMV-NP preparation.
• Characterization included zeta potential, lipid membrane dynamics (Laurdan assay), and enzymatic activity (Nox).

Main Results:

• Successfully synthesized OMV-NPs by covalently coupling AuNPs to OmpA within OMVs using bioorthogonal click chemistry.
• Developed a simplified low-speed centrifugation protocol for OMV-NP production.
• Characterized OMV-NPs, confirming their stability and functionality, including enzymatic activity and lipid membrane dynamics.
• Demonstrated successful coupling of AuNPs to OMVs derived from attenuated bacteria expressing specific surface proteins or antibody fragments.
• Validated OMV-NPs displaying EGFR-targeting antibody fragments for specific binding to tumor cells, showcasing potential for targeted therapy.

Conclusions:

• Bioorthogonal click chemistry provides an effective strategy for creating functional OMV-NPs.
• The developed method offers a simplified and scalable approach for OMV-NP production.
• OMV-NPs hold significant promise for targeted drug delivery and therapeutic applications, particularly in oncology.