Membrane Anchored-DNA Tetrahedron For Rapidly Bacterial Outer Membrane Vesicles Isolation And Extraction

Outer membrane vesicles(OMVs)are spherical lipid bilayer nanostructures naturally secreted by bacteria,which have many functions.Such as bacteria-bacteria,bacteria-host interaction.OMVs are vesicular complexes containing bioactive substances and have unique structure,abundant antigenic components and good immunogenicity.Studies have shown that OMVs are an important way for bacteria to transport virulence factors and interfere with host immune defense system,which play an important role in bacterial infection.The diverse physiological and pathological functions of OMVs make them have broad prospects in biomedicine and nanotechnology.Therefore,it is very important for the rapid and effective isolation of bacteria and the development of vaccines for cancer.At present,the most commonly used method to obtain OMVs is ultra-speed centrifugation,but this method is not only complicated and time-consuming,but also requires professional operators.Moreover,the machine is very expensive and potentially risky to operate,for a variety of reasons,so it is necessary to develop a fast and efficient separation and extraction OMVs technology.In this context,this paper takes advantage of the good controllability,Biocompatibility and modifiability of DNA tetrahedrons and combines them with hydrophobic cholesterol,a simple and stable membrane-anchored DNA tetrahedron(TDN)was designed and constructed for isolation and isolation of E.coli OMVs.OMVs were enriched and extracted by combining TDN with Streptavidin immunomagnetic beads,using membrane anchoring and magnetic adsorption.The experimental data show that the TDN can effectively anchor on the surface of OMV.The OMVs obtained by this method are between 20 and 200 nm in size,showing colorless and transparent spherical vesicles with smooth and regular edges.The results are consistent with those reported in the literature.The experimental results show that this method can not only extract OMVs quickly and effectively,but also has similar results with OMVs obtained by ultracentrifugation in morphology,protein speciesand,and so on.Therefore,the enrichment strategy of OMV anchored by functional modified DNA is expected to be a new method for isolation and extraction of OMV before analysis.