Tecnai 12 microscope

UV-Vis spectra were acquired with a double beam spectrophotometer (Shimadzu UV-1601) in the 250−800 nm wavelength range. Quartz cuvettes (optical path 1 cm, Optech, München, Germany) were used. Localized surface plasmon resonance (LSPR) peak positions were estimated on at least three replicates for each type of nanocolloid. TEM was performed with a FEI Tecnai 12 microscope (Eindhoven, Netherlands), equipped with a LaB₆ filament operating at 120 kV. Size distribution histograms were obtained with OriginPRO 2016 software, after TEM images processing performed by ImageJ software [33 ], manually highlighting individual NPs on each micrograph. Histograms were produced on three replicates, counting more than 800 nanoparticles. X-ray photoelectron spectroscopy measurements were performed on both steel rods and gold colloids deposited on silicon substrates, using a PHI Versaprobe II (Chanhassen, MN, USA) spectrometer equipped with monochromatized Al-Kα radiation (1486.6 eV), following a previously reported procedure [34 (link),35 (link)]. Binding energy (BE) scale was corrected on C1s component at 284.8 eV. Au4f region was fitted using CasaXPS^® version 2.3.19PR1.0, selecting a sum function of Gaussian with a Lorentzian (SLG) for the Au⁽⁰⁾ component and a product function of a Gaussian with a Lorentzian (GL) for the Au^(I) and Au^(III) components.

The extinction spectra were obtained on the Shimadzu UV–3600 plus ultraviolet/visible/near-infrared spectrophotometer (Shimadzu, Kyoto, Japan). Transmission electron microscopy (TEM) imaging was carried out on an FEI Tecnai 12 microscope operated at 120 kV. The sheet resistance was measured on the four–probe methods (RTS–8) based on the linear four–probe technology. PET was treated by the plasma cleaner (CPC–A). Atomic force microscopy (AFM) images were got by Asylum Research MFP–3D–SA with repulsive force in tapping mode. X-ray diffraction (XRD) image was obtained via a Panalytical Empyrean diffractometer using Cu Kα radiation (λ = 1.5406 Å) in the ranges of 20° to 80°.

TEM sample preparation was performed via focused ion beam (FIB) milling with Ga ions using a FIB/SEM Dual Beam Microscope FEI NOVA 200. The lift out and initial milling step was done with 30 kV ions and the final milling step was performed at 5 kV. The resulting lamellae were mounted onto an Omniprobe copper-based lift-out grid and directly transferred to the microscope. STEM observations were carried out by a probe corrected FEI TITAN³ G2 microscope operated at 300 kV in scanning mode. Selected area electron diffraction (SAED) experiments were performed using a FEI Tecnai 12 microscope, operated at 120 kV. TEM samples were prepared from both the surface as well as from the inside of the cuboids after careful cracking.

Cells were fixed in 2.5% glutaraldehyde, washed for 5 min in 0.1 M cacodylate buffer then post-fixed in 1% OsO₄ in 0.1 M cacodylate buffer for 30 min. Cells were washed three times with water and stained with 3% uranyl acetate for 20 min. After another rinse with water, cells were dehydrated by sequential 10 min incubations with 70, 80, 90, 96, 100 and 100% ethanol before embedding in Epon at 70°C for 48 h. Thin 70 nm serial sections were cut and stained with 3% uranyl acetate then lead citrate, washing three times with water after each. Once dried, sections were imaged using an FEI Tecnai12 microscope.