Veleta 4k ccd camera

Freshly prepared nanoparticles were sedimented on an formvar-coated, carbon-sputtered copper grid. After negative staining with 1% phosphor-tungstic acid, pH 7, the samples were analysed at 80 kV on a Tecnai 12 electron microscope (Fei, Eindhoven, The Netherlands). Images of selected areas were documented with Veleta 4k CCD camera (Emsis, Münster, Germany).

Overnight cultures of EAEC strain 55989 agg3⁻ carrying one of the plasmids pAAF/I, pAAUF/III, pAAF/IV, pAAF/V, and pBAD24 were diluted in fresh LB medium containing ampicillin (100 µg/ml) and cultivated at 37°C until an OD₆₀₀ of 0.4–0.6 had been reached. Then, 10% arabinose solution was added to a final concentration of 0.3% for the induction of AAF fimbrial expression, and the incubation was continued for another 60 minutes at 37°C. A drop of bacterial culture of each sample was sedimented on a Formvar-coated, carbon-sputtered grid. After negative-staining with 1% phosphotungstic acid, the samples were analyzed at 80 kV with a Tecnai 12 electron microscope (FEI, Eindhoven, The Netherlands). Images of selected areas were documented with Veleta 4k CCD camera (emsis, Münster, Germany).

Electron microscopy enabled visualization of the extracellular vesicles to ensure that they are of typical shape and size, and are intact after isolation. Negative staining was used to visualize the isolated extracellular vesicles. Extracellular vesicles (5 μl) were sedimented on Formvar-coated, carbon-sputtered cupper-grids.
After negative staining with 1 % phosphotungstic acid for 2 min, the samples were dried on filter paper and afterwards analyzed at 80 kV on a Tecnai 12 electron microscope (FEI, Hillsboro, Oregon). Images of selected areas were documented with Veleta 4 k CCD camera (emsis, Muenster, Germany).