Tecnai spirit transmission electron microscope

Ten microliter of tau K18 or 244-378 fibril solution was dropped onto 200-mesh Formvar carbon–coated nickel grids (Electron Microscopy Sciences) for 20 min after which samples were stained with 25% uranyl acetate replacement (Electron Microscopy Sciences) for 10 min. Before the analysis, the staining solution was removed using Whatman filter paper, and the grids were air-dried for 5 min. Samples were visualized using a FEI Tecnai Spirit Transmission Electron Microscope operating at 120 kV and equipped with an Olympus MegaView G2 camera.

The TEM analysis was conducted at the Microscopy
Imaging Center (MIC) at the University of Bern. A FEI Tecnai Spirit
transmission electron microscope operated at 80 kV and equipped with
an Olympus-SIS Veleta CCD Camera was used for recording the micrographs.
The as-prepared catalyst samples were prepared by dispersing catalyst
powder in ethanol and dropping the catalyst suspension onto TEM copper
grids. The samples exposed to electrochemical measurements and potentiostatic
tests were collected by scraping the catalysts off the GDLs and dispersing
them in ethanol. TEM micrographs were collected from five independently
selected areas for each analyzed sample.
The same equipment
and a gold finder grid were used for the IL-TEM analysis. Concerning
sample preparation, the Pt + 5Au/C catalyst powder was dissolved in
the mixture of IPA and H₂O (V_IPA/V_H2O = 3:1), and 7 μL
of Nafion was added to lead to the weight ratio between Nafion and
carbon support of 1:1. The catalyst ink was diluted by a factor of
10, and 10 μL of the diluted ink was pipetted onto a Au grid
for IL-TEM analysis before electrochemistry. Afterward, the same Au
grid was placed between a Nafion membrane and GDL in the GDE setup,
and after the FAOR potentiodynamic test, the Au grid was analyzed
with IL-TEM.