S 4700 type 2

Biofilms were examined by SEM and CLSM (Djeribi et al., 2012 (link)). For SEM examination, biofilms were developed at 37 °C for 24 h in polystyrene coverslips placed into a 24-well plate with MHB containing bacterial cells (OD_600nm 0.01) added. After fixed in 3.7% formaldehyde for 40 min at room temperature and then rinsed twice with PBS, further fixation was performed with 1% osmium tetroxide for 15 min at room temperature and then rinsed twice with PBS. The samples were then dehydrated by passing them through different concentrations of ethanol: 35%, 50%, 70%, 80%, and 95%, each for 5 min, followed by 100% ethanol twice for 10 min each time. The samples were then dried at 60 °C for 24 h. After being coated with gold-palladium (via sputter coating), the samples were examined under a bioscanning electron microscope (Hitachi, S-4700, Type II).
For CLSM examination, biofilms formation in polystyrene coverslips and fixation in 3.7% formaldehyde were the same as mentioned above. Then the samples were stained with a prepared 100 nM solution of Syto-9 stain (Invitrogen, Carlsbad, CA) for 30 min (Luo et al., 2015b (link)). Syto-9 stained biofilms were excited with a 488 nm solid-state laser, and fluorescence was captured between 500–550 nm. The images of biofilms were rendered and assembled using appropriate computational software (ZEISS LSM780).

The selected ME flakes and structural
domains were identified by an optical microscope, and then, morphological
and spectroscopic measurements were performed. Raman spectroscopy
analysis was carried out with a Senterra II Compact Raman microscope
(Bruker) using 532 nm laser excitation wavelength, operating at a
power of ≤2.5 mW and a 50× objective. Atomic force microscopy
(AFM; NT-MDT Solver AFM microscope) operated in “tapping”
mode with a silicon tip on a silicon nitride lever (Nanosensors, Inc.,
SSS-NCH-type 15 μm long silicon needle with a 10° half
cone angle and 2 nm radius of curvature) was also used to analyze
samples. The 2D dispersions were characterized morphologically (measuring
lateral size) capturing transmission electron microscopy images (TEM;
FEI Tecnai G₂ 20 X-Twin type, operating at an acceleration
voltage of 200 kV). Analysis of TEM images was performed using ImageJ
software, determining the lateral size of each flake and performing
statistical analysis on 100 flakes. The morphology of MoSe₂ and WSe₂ films on FTO electrodes was characterized by
scanning electron microscopy (SEM; Hitachi S-4700 Type II, operating
at 10–15 kV). The absorption spectra of the deposited MoSe₂/FTO and WSe₂/FTO films were acquired by an Agilent
8453 UV–visible diode array spectrophotometer in the range
of 400–1000 nm.

The X-ray diffraction (XRD) patterns of the synthesized ZVI NP samples were recorded at a scan rate of 4° (2θ)/min using monochromatic Cu K_α radiation (MXP18; MAC Science, Japan) at 30 kV and 20 mA. The recorded specific peak intensity and 2θ values were further identified using a database system (JCPDS). The morphology, microstructure, and particle size of the ZVI NPs were investigated by field-emission scanning electron microscopy (FE-SEM; S-4700 Type II; Hitachi, Japan) and high-resolution transmission electron microscopy (HR-TEM; H-7500; Hitachi, Japan).