Tecnai g2 f20

The crystalline microstructures of the samples were examined by XRD (X-ray diffraction, Rigaku D/Max-2400 diffractometer, Cu Kα radiation, λ = 0.15406 nm) in the range of 10–80° with a scanning speed of 2° min⁻¹. The applied tube voltage and current were 40 kV and 30 mA, respectively. The element types, valence states and detailed chemical bonding energy were investigated by X-ray photoelectron spectroscopy (XPS, Kratos AXIS Ultra DLD, Al Kα probe beam, the applied photoelectron energy hv = 1486.6 eV), and the nanofiber sample was pressed into a film by a tablet press and evacuated for 1 day before testing. The fitting software of the high-resolution spectra was XPS Peak.
To prepare the FE-SEM (field-emission scanning electron microscopy, S-4800, Hitachi) characterization, the sample is glued to the metal table with conductive glue. In addition, a TEM (transmission electron microscopy, FEI, Tecnai G² F20) with EDX (energy dispersive X-ray) spectroscope was applied to acquire the detailed microstructure and composition. During the sample preparation, the sample was first put into an alcohol solution and ultrasonicated for about 10 min. Next, a dropper was used to draw a small amount of supernatant onto the micro-grid. Finally, the micro-grid with the sample was dried for a few minutes to evaporate alcohol.

EV samples were stained with fluorescein isothiocyanate (FITC) mouse antihuman CD9 (555371) and PerCP-Cy™5.5 mouse antihuman CD63 antibodies (565426) from BD Biosciences (San Jose, CA, USA) for 30 min at room temperature under dark lighting. EVs were acquired using an Accuri C6 flow cytometer (BD Biosciences), and analysis was performed using FlowJo software (Treestar, Inc., San Carlos, CA, USA). EVs stained in the same way were also analyzed using confocal microscopy with a Carl Zeiss microscope (LSM900, Zeiss, Oberkochen, Germany). Image analysis was performed using ZEN3.0 (blue edition) software.
Transmission electron microscopy (TEM) analysis was performed by fixing EV pellets with 4% paraformaldehyde (PFA) and then by negative-staining them with 1% uranyl acetate. The equipment used for analyzing EVs mounted on the grid was Tecnai™ G2-F20 (FEI, OR, USA).

A thin film with a thickness of about 0.60 mm was fabricated from the steel sheet. Thin foil specimens for transmission electron microscopy (TEM, FEI, Hillsboro, OR, USA) and electron energy loss spectroscopy (EELS, JEOL, Tokyo, Japan) analysis were mechanically polished to about 50 μm thickness, punched to disks of 3 mm diameter, and then electropolished in the solution that contains 10% perchloric acid and 90% glacial acetic acid. At a temperature of −30 °C and a current of 35–160 mA, electrolytic double spray was used for 2 to 3 min. TEM observation was performed in a FEI Tecnai G2 F20 (Hillsboro, OR, USA) field emission transmission electron microscope operated at an accelerating voltage of 200 kV.
The 10% perchloric acid alcohol solution was used for electrolytic polishing of scanning electron microscope (SEM, JEOL, Tokyo, Japan) samples, with voltage of 26 V, current of 0.6 A, and polishing time of 25–30 s. The boundary properties were examined by electron back-scattered diffraction (EBSD) using a JEOL JEM-7800F field emission scanning electron microscope equipped (Tokyo, Japan) with an Oxford BESD detector (Oxford, UK). The EBSD data were analyzed using CHANNL 5 software (HKL, Danbury, CT, USA).