Su4800

Samples of inoculated surfaces of the adhesive Scotch-Weld 2216 B/A were prepared on a dual-beam FIB/SEM workstation (FEI Helios Nanolab) and investigated by field emission scanning electron microscopy (FESEM) using a Hitachi SU-4800 instrument operated at 1 kV. Prior to inserting the sample in the FIB, a thin Au layer was sputter-deposited on the surface of the sample to protect the polymer in the subsequent preparation steps. FESEM scanned the specimen in a grid to create an image. FIB cut out a 10 µm by 10 µm test area with an ion beam perpendicular to the specimen surface, which was then sectioned by the ion beam in 1 µm steps. Images were taken by an SEM vertically oriented to the ion beam. FESEM images of PVA, and inoculated and non-inoculated Scotch-Weld 2216 B/A allowed visualization of embedded spores in the adhesive. FIB/SEM images verified the partial embedding of the spores necessary for further staining approaches (see Fig. 1).

Thermogravimetric analysis (1100SF) was employed to characterize the thermal decomposition of as-spun TiO₂ nanofibers in air atmosphere with a heating rate of 10 °C/min. X-ray diffraction patterns of porous TiO₂ nanofibers were recorded on a Bruker D8 Advance X-ray diffractometer with Cu Kα radiation (wavelength λ = 1.54 Å) at a scanning speed of 4 °C/min. A Hitachi field emission scanning electron microscope (FE-SEM, SU4800) was employed to observe the surface morphology of porous TiO₂ nanofibers. Prior to the FE-SEM examination, all the specimens were sputter-coated with gold to avoid charge accumulations. Transmission electron microscopy was conducted on a JEOL JEM-2100 transmission electron microscopy unit at an accelerating voltage of 120 kV. The specific surface area and pore structure of porous TiO₂ nanofibers were characterized with a physisorption analyzer (ASAP 2020, Micromeritics).

The FTIR spectra were collected from PerkinElmer Spectrum II FT-IR Spectrometer. The ¹H NMR spectra were acquired on a Bruker AVANCE III HD 400 NMR spectrometer using deuterated DMSO as the field frequency lock. The ⁶⁷Zn NMR spectra were acquired on a Bruker AV 600 NMR spectrometer using deuterated DMSO as the field frequency lock. The SEM images were collected from Hitachi SU4800. The ex situ SEM samples were obtained by disassembling the cell, extracting the electrode, washing by DI water for 3 times, and drying at vacuum (~25 °C) for 8 h.The DLS measurement was performed on DLS instrument (Zetasizer Nano ZS, Malvern Instruments Ltd) at 25 °C with scattering angle of 90° and laser wavelength of 632.8 nm. The ionic conductivities of the electrolytes were measured on a conductivity meter (DDS-11A, INESA) at ~25 °C.

The structure and morphology of the thin-film samples, before and after sulfurization, were investigated by the grazing-incidence X-ray diffraction technique (GIXRD, SmartLab, Rigaku Corp., Tokyo, Japan) at room temperature using Cu Kα radiation (λ = 1.5406 Å) at 50 mA and 40 kV power, and the incident beam was set at fixed critical w angles (0.2° ≤ w ≤ 0.8°). The layered structures were analyzed by micro-Raman spectroscopy (HORIBA T64000, Kyoto, Japan) using a 515 nm laser source. The surface morphology and the elemental composition mapping of the thin-film sample were analyzed by field emission scanning electron microscopy (FE-SEM, Hitachi SU4800, Tokyo, Japan) at 10–15 kV coupled with an energy-dispersive X-ray (EDX) analysis device, and high-resolution observations of the powder scratched from the thin-film sample were performed by a high-resolution transmission electron microscope (HRTEM, JEOL 2100F, Tokyo, Japan) equipped with an EDX analysis device. The electron binding energy spectra of the thin-film samples were measured by X-ray photoelectron spectroscopy (XPS, ULVAC Quantum-2000, Chigasaki, Japan) using Al Kα radiation at 15 kV and 50 W and a take-off angle of 45°. All the binding energies were calibrated versus the C 1s peak of the adventitious carbon at 285 eV.

Following the incubation, uncoated or pECM- or hECM-coated scaffolds with or without seeded cells were fixed in 2.5% glutaraldehyde (Sigma–Aldrich, St. Louis, MO, USA) solution in phosphate-buffered saline (PBS, Sigma–Aldrich, St. Louis, MO, USA) for 1 h at room temperature, then rinsed three times with PBS. The samples were lyophilized for a minimum of 4 h, sputter-coated with gold-palladium, and evaluated using scanning electron microscopy (SEM, SU4800, Hitachi, Japan). The diameters of 280 individual fibers per condition were measured with ImageJ software (National Institutes of Health, Bethesda, MD, USA) from 14 different SEM images of each scaffold type. The 14 images with a clear focus on a single plane were selected from 18 images randomly captured from 6 replicates (two rounds of 3 replicates/round for each condition).

The micromorphology of the materials was observed by SEM (SU-4800, Hitachi, Japan) and TEM (JEM-2100F, JEOL, Japan). The crystal structure of the materials was analyzed by XRD (Bruker D8, using filtered Cu Kα radiation). The degree of defects in the materials was analyzed by a Raman spectrometer (Vertrex 70, Bruker, Germany) with a laser excitation wavelength of 532 nm. The exact content of elemental Fe in the material was obtained by ICP-OES (Optima 8000, PerkinElmer, USA). N2 adsorption/desorption tests were conducted at 77 K by a gas adsorption analyzer (ASAP 2020, Micromeritics, USA). The specific surface area and pore size of the samples were calculated by Brunauere–Emmette–Teller (BET) and Barrett–Joyner–Halenda (BJH) models, respectively. The chemical composition of the catalyst was analyzed by XPS (ESCALAB 250, Thermo Scientific, USA).