Solutions were
diluted 100-fold at either 20 or 5 °C to generate 0.10% w/w dispersions.
Images obtained at lower pH were prepared by diluting dispersions
using acidified water at the desired solution pH. Copper/palladium
TEM grids (Agar Scientific, UK) were surface-coated in-house to yield
a thin film of amorphous carbon. The grids were then plasma glow-discharged
for 30 s to create a hydrophilic surface. Individual samples (0.10%
w/w, 12 μL) were adsorbed onto the freshly glow-discharged grids
for 60 s and then blotted with filter paper to remove excess solution.
To stain the aggregates, a 9 μL drop of 0.75% w/w uranyl formate
solution was soaked on the sample-loaded grid for 20 s and then carefully
blotted to remove excess stain. The grids were then dried using a
vacuum hose. Imaging was performed at 80 kV using a FEI Tecnai Spirit
microscope equipped with a Gatan 1kMS600CW CCD camera.
diluted 100-fold at either 20 or 5 °C to generate 0.10% w/w dispersions.
Images obtained at lower pH were prepared by diluting dispersions
using acidified water at the desired solution pH. Copper/palladium
TEM grids (Agar Scientific, UK) were surface-coated in-house to yield
a thin film of amorphous carbon. The grids were then plasma glow-discharged
for 30 s to create a hydrophilic surface. Individual samples (0.10%
w/w, 12 μL) were adsorbed onto the freshly glow-discharged grids
for 60 s and then blotted with filter paper to remove excess solution.
To stain the aggregates, a 9 μL drop of 0.75% w/w uranyl formate
solution was soaked on the sample-loaded grid for 20 s and then carefully
blotted to remove excess stain. The grids were then dried using a
vacuum hose. Imaging was performed at 80 kV using a FEI Tecnai Spirit
microscope equipped with a Gatan 1kMS600CW CCD camera.