Tecnai g2 f20 transmission electron microscope

Surface morphology analyses of particles were performed using a Tecnai G2 F20 transmission electron microscope (TEM, FEI). Particle size and zeta potential measurements were carried out with a Nano‐ZS90 Zetasizer. The fourier transform infrared (FTIR) spectra were characterized using a 5DX FT‐IR spectrometer (Nicolet). The UV‐vis spectra were measured by a U‐3900H UV‐vis spectrophotometer (Hitachi), and the fluorescence spectra were recorded by a RF‐5301PC photoluminescence spectrometer (Shimadzu). Capillary electrophoresis analyses were performed on a Qsep100 Bio‐Fragment Analyzer (BiOptic). Fluorescence lifetime was recorded using a PPD‐850 fluorescence‐photon counting detector (HORIBA, Japan).

For TEM analysis, the exponential-phase E. coli ATCC25922 and Salmonella enterica subsp. enterica ATCC51741 (1 × 10⁸ CFU/mL) cells were treated with 1×, 1.5× and 2× MIC of the peptide UTNGt21O for 6 h at 37 °C following the protocol as previously described [21 (link)]. Ultrathin sections were prepared and coated on copper grids and stained with uranyl acetate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA) and lead citrate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA). The grids (10 random sections per treatment) were examined using the Tecnai G2 F20 transmission electron microscope (FEI Company, Hillsboro, OR, USA).

The test bacteria were treated independently with the peptide extracts at 1 X and 2 X MIC and incubated for 24 h at 37°C. The peptide extract was washed away thrice by using sodium phosphate buffer by centrifuging at 10,000 × g for 15 min. The cells were fixed with 2.5% glutaraldehyde and stored overnight at 4°C. The buffers and dehydration protocol used were developed by the Laboratory of Electronic Microscopy, University of Antioquia (Medellin, Colombia). Briefly, the samples were washed thrice with cacodylate buffer and postfixed for 1 h with osmium tetroxide 1% and cacodylate buffer in 1 : 1 ratio. Then, they were washed thrice in cacodylate buffer (10 min) and incubated overnight in the same buffer. The samples were then washed thrice with water, once with uranyl acetate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA), and again thrice with water. The samples were dehydrated in a graded ethanol series and embedded in Epon (resin). Ultrathin sections were prepared and coated on copper grids and stained with uranyl acetate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA) and lead citrate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA). The grids (10 random sections per treatment) were examined using the Tecnai G2 F20 transmission electron microscope (FEI Company, USA). Untreated cells of Salmonella were used as control.

The morphology of the PVA and CFG/PVA nanocomposite films was analyzed using a Tecnai G2 F20 Transmission Electron Microscope (TEM) from FEI Company, Boston, MA, USA. Samples were prepared on a copper grid and observed under an accelerating voltage of 200 kV, achieving a point resolution of 0.24 nm and an information resolution of 0.14 nm, with the electron gun set to an energy resolution of ≤0.7 eV. This high-resolution imaging provided critical insights into the microstructural details of the nanocomposites, which are crucial for understanding the distribution and interaction of CFG within the PVA matrix.

X-ray diffraction (XRD), Rigaku D/Max 2500 diffractometer with Cu-Kα radiation (Rigaku, Tokyo, Japan) was used to identify the phase constitution of the Zr-16Nb-xTi alloys. The accelerating voltage and current used were 40 kV and 250 mA, respectively. Transmission electron microscopy (TEM) was employed to examine the microstructure of the Zr-16Nb-xTi alloys. The Tecnai G2 F20 transmission electron microscope (FEI Company, Hillsboro, Oregon, USA) was used to observe the microstructure of the Zr-16Nb-xTi alloys at 200 kV.

Powder X-ray diffraction patterns (PXRD) were obtained by a Bruker D8 Advance diffractometer (0–2ϴ) using Cu K_α radiation (λ = 1.5418 Å). Transmission IR spectra were recorded in the range of 400–4000 cm⁻¹ on a Nicolet iS5 iD7 ATR spectrometer. N₂ sorption isotherms were obtained at 77 K using an ASAP porosimeter (accelerated surface area and porosimetry system, model 2013; Micromeritic) connected to a computer. Prior to the analysis, samples were evacuated at 120 °C under primary vacuum. Brunauer–Emmett–Teller (BET) surface area and pore volume were estimated at a relative pressure ranging from 0.05 and 0.25. Field emission gun scanning electron microscopy (FEGSEM) observations were obtained by using a TopconSM-300 microscope with a secondary electron detector and an electron acceleration voltage of 10 kV. Dual beam focused ion beam scanning electron microscope (FIB/SEM) images were obtained by using an FEI microscope (HELIOS NANOLAB 600i) with a gallium ion column. HRTEM images were recorded on a FEI Tecnai G² F20 transmission electron microscope (TEM) operating at 200 kV, equipped with an electron scattering transmission emission. Samples were prepared by the deposition of one droplet of colloidal suspension onto a carbon-coated copper grid, which was left to air dry.