Em420

Peptide nanostructures were imaged by preparing 0.1 wt% (1 mg mL^–1) peptide solutions in Milli-Q water. Samples were adsorbed for 5 minutes at 25 °C onto 200 mesh copper grids coated with Formvar in carbon film and were stained with a 2% uranyl acetate solution. The grids were allowed to dry prior to imaging. Images were acquired using a Philips EM 420 transmission electron microscope equipped with an SIS Megaview III CCD digital camera, at an accelerating voltage of 100 kV.

Imaging was performed using a Philips EM420 as described before [31 (link)].

Negative stain electron microscopy was used to visualize FtsZ filaments as described previously^{41 (link)}. Samples of PaFtsZs with or without ZipA or ZapA were incubated with GTP to polymerize for 1–5 min at room temperature. Then, 10 µl samples were applied to a carbon-coated copper grid for about 5 s and then quickly dried with filter papers. Grids were immediately stained with several drops of 2% uranyl acetate. Images were obtained on a Philips EM420 equipped with a CCD camera.

Transmission electron microscopy (TEM) was used to characterize the sizes of TOCNs used in this work. Images were acquired using a JEOL 2100 Transmission Electron Microscope (JEOL, Ltd., Peabody, MA, USA) and previously described imaging techniques [43 (link)].
Transmission electron microscopy was also conducted in order to directly visualize the membrane layers of interest. Specimens were prepared by cutting radial slices from the interior of the film samples and set in Epo-Fix epoxy resin to cure for 24+ h. An RMC Powertome PC (Boeckeler Instruments, Tucson, AZ, USA) microtome was used at room temperature to collect electron transparent sections on 3 mm hexagonal mesh copper grids.
Analysis was performed on a thermionic Philips EM420 transmission electron microscope at an acceleration voltage of 120 kV. Images were acquired in bright-field conditions and recorded on a charge-coupled device (CCD) camera. Fiji [36 (link)] was used to process the images and measure the thicknesses of the polyamide skin layers.

The X-ray diffraction patterns were collected with a diffractometer (D8 Advance, Bruker, Karlsruhe, Germany) using nickel filtered Cu K-alpha source with λ = 0.154 nm. Catalyst morphology and composition were investigated by scanning electron microscopy (SEM)/energy dispersive x-ray spectroscopy (EDX) (XL 40, Philips, Eindhoven, The Netherlands) and transmission electron microscopy (TEM) (EM 420, Philips, Eindhoven, The Netherlands). The GDE/electrolyte drop interface was studied by contact angle goniometer (OCA 15Pro, Dataphysics, Filderstadt, Germany) in ambient air at 23 °C. In order to study the reaction products during the zinc/air discharge step, a side-by-side optical cell (ECC-opto-SBS, El-Cell, Hamburg, Germany) and a confocal Raman microscope (InVia Reflex, Renishaw, Kingswood, UK) were employed. The laser beam (Ar, 532 nm, 2 mW) was focused through a 50× objective lens (DM 2500, Leica, Mannheim, Germany) with ~1 mm spot size. A high-resolution diffraction grating density of 1800 grooves mm⁻¹ was employed. A single spectrum consisted of 20 accumulated scans with an acquisition time of 20 s each. The background signal was subtracted according to the baseline correction mode.

The Pd nanoparticles were prepared by solvothermal technique, exploiting the Bradley reaction, using a modified procedure [13 (link)]. Palladium acetylacetonate (99%, Aldrich CAS No 14024-61-4) ca. 0.2 g was dissolved in 20 ml of 99% acetophenone (>98% Aldrich CAS no 98-86-2) and subjected to reflux in 4 h. The color of the solution then changed from reddish brown to black. The formed particles were separated by centrifugation and washed by 3 portions of 10 ml 99.5% ethanol and dried in vacuum.
To characterize the Pd nanoparticles, the SEM-EDS investigation of the samples was carried out with a tabletop Hitachi TM 1000-μ-DeX scanning electron microscope. The size of individual Pd nanoparticles was established by image analysis in TEM using Philips EM 420 transmission electron microscope. The thus determined size was well correlating with that determined by Debye-Scherrer formula applied on the X-ray powder diffraction data. X-ray powder diffraction study was made with a multifunctional Bruker SMART Apex-II diffractometer operating with a MoKα radiation (l = 0.71073 Å). In solution (ethanol or KSFM medium) the hydrodynamic size of the aggregates was determined by Laser reflection microscopy (NanoSight, Malvern Instruments Ltd, Malvern, UK)