Geminisem 300

Scanning electron microscope (SEM) was used to observe the ultrastructural changes of the duodenum. Samples were rinsed twice in cold PBS and fixed with 2.5% glutaraldehyde solution overnight at 4°C. After being fixed, the tissues were trimmed into 3 mm³ and washed three times with precooled PBS, followed by successively dehydration using 30, 50, 70, 85, 95, and 100% alcohol, the tissue blocks were dried in the dryer and sprayed with gold. Then, Geminisem 300 Zeiss field emission scanning electron microscope system (Geminisem 300, Carl Zeiss, Germany) was applied to observe and photographing the changes in morphological structure of duodenum.

X-ray diffraction patterns were obtained with a Shimazu XRD-6100 diffractometer with Cu Kα radiation (40 kV, 30 mA) of wavelength 0.154 nm (Kyoto Japan). Scanning electron microscopy (SEM) images were collected on GeminiSEM 300 from Carl Zeiss Microscopy GmbH (Oberkochen, Germany). Energy-dispersive X-ray spectroscopy (EDS) was recorded on a Gemini SEM 300 scanning electron microscope (ZEISS; Oberkochen, Germany) at an accelerating voltage of 5 kV. Transmission electron microscopy (TEM) images were obtained using an H-800 electron microscope and an H-8010 scanning system (Hitachi, Japan). X-ray photoelectron spectroscopy (XPS) data were measured on Thermo Scientific K-Alpha with Al Kα radiation. The zeta potential was conducted on a Malvern Nano ZS90 Zetasizer Nano instrument (Worcestershire, UK). The ultraviolet–visible (UV–Vis) absorption spectra were received on a UV-2900 spectrophotometer.

An angular-solved THz-time domain spectroscopy (TDS) setup is used to measure the transmission properties at oblique incidence from the hybrid metal–graphene metastructure. The source laser is a Ti/Sapphire laser (Spectra Physics, MaiTai, CA, USA) with a pulse width of 200 fs and repetition rate of 75.9 MHz at 800 nm, which further impinge onto a photoconductive switch integrated on low-temperature grown GaAs (LT-GaAs) at an average power of 30 mW. The switch is biased at 40 V and produces the linear polarized THz pulses that propagate in a nitrogen-purged environment through the sample, with probe detection performed via an LT-GaAs-based photoconductive switch as well. The spot size of the THz pulse is approximately 3 mm with a frequency resolution of ~50 GHz. By rotating the sample, the incident angle of the light is typically set to 0–30° for the angular-resolved THz transmission measurement.
The morphology of the metastructure is characterized by field emission scanning electron microscopy (SEM, ZEISS GeminiSEM 300, ZEISS, Jena, Germany). Graphene properties are characterized by Raman spectroscopy (Laboratory Ram HR800, CA, USA, excitation wavelength at 532 nm). The electrical properties of the device are measured using a sourcemeter (Agilent 2400 and 2401).

Scanning electron microscopy (SEM) images of electrospun fibers were taken with a Zeiss Gemini SEM 300 (Carl Zeiss, Oberkochen, Germany). The sample was prepared by cutting the glass slide with the electrospun fibers into a small square shape (1 cm × 1 cm) and mounting it on an aluminum stub using conductive tape. The sample was then sputter-coated with a thin layer of gold. SEM images were collected using an accelerating voltage of 5 kV, a working distance of 7.2 mm, and a magnification of 1140×.

Starch granules were extracted as previously described (Zhang et al., 2022 (link)). A scanning electron microscope (SEM), ZEISS Gemini SEM300 (Carl ZEISS AG, Oberkochen, Germany), was used to analyze and record the morphology of the starch granules. The starch granules were evenly distributed on the tape stuck on the loading platform for observation. As per the instrument instruction, each sample was viewed under three different fields and the morphology of the starch granules was observed at 1,000× and 2,000× magnification.

The metal content was analyzed by ICP-MS (iCAP RQ, Thermofisher Scientific, Foster, CA, USA). For transmission electron microscopy (TEM), the samples were examined in the Hitachi H-7650 instrument at 60–80 kV. The samples were observed for scanning electron microscopy (SEM) under a ZEISS Gemini SEM 300 (Carl Zeiss, Oberkochen, Baden-Württemberg, Germany).
The root samples of HM and PH groups were collected, embedded in resin, then sliced into 5 μm slices by a slicer (LKB Bromma ultratome pyramitome 11800, Stockholm, Sweden). Subsequently, the ultrathin section was map-scanned by a micro-confocal Raman spectrometer (inVia-Reflex 532/XYZ, Renishaw, London, UK).