Mc1000

The scanning electron microscopy (EVO 18, Zeiss, Germany) was utilized to observe and assess the morphology of the CNFs. The accelerating voltage of SEM was 10 kV. And the detector was secondary electron. The samples were dropped onto the mica plate after dilution. And it was coated with a layer of gold in vacuum atmosphere using an ion sputter (Hitachi, MC1000) after drying at room temperature overnight to ensure its electrical conductivity before testing. Thickness of the gold on the samples was around 30 nm. The SEM images were applied to measure the lengths and diameters of the CNFs by using Nano-Measurer 1.2 software. For each CNF sample, one thousand and five hundred fibers from different SEM pictures were used to evaluate their lengths and widths. Lengths and widths of the fibers were measured manually. Lines were carried out along the actual shape of the CNFs to measure their lengths with the utilization of Nano-Measurer 1.2.

ApoV-HS and PBS-HS were compressed and injected into DI (1 mL) in an Eppendorf tube. After 10 min, ApoV-HS and PBS-HS were hydrated, frozen at − 80 °C overnight, and then subjected to lyophilization for 30 h using a − 80 °C freeze drier. The freeze-dried PBS-HS and apoV-HS were sprayed with gold by Sputter Coater (MC1000, Hitachi, Japan) for electric conduction, and observed by Scanning electron microscope (SEM, Quanta200, Thermo Fisher, USA).

For scanning electron microscopy (SEM), deposited glass slides (Lab-Tek and Shell-vial 12 mm) were fixed with glutaraldehyde 2.5% in 0.1 M of sodium cacodylate buffer for 60 min. Slides were rinsed with 0.1 M sodium cacodylate buffer and distilled water for 1 minute each. Slides were dehydrated with increasing ethanol solutions (30%, 50%, 70%, 90%) for 2 minutes and with 100% ethanol for 5 minutes. Slides were incubated with 100% ethanol/100% hexamethyldisilazane (HDMS) in a 1:2 ratio for 5 minutes. Slides were incubated with 100% of HDMS for 5 minutes and air-dried for 30 min. We checked that no particles had been lost after this virus preparation (dehydration and drying) for SEM (not shown). Finally, the slides were platinum sputter-coated for 20 s at 10 mA (Hitachi MC1000). The observation was made using a SU5000 (Hitachi High-Technologies, Tokyo, Japan) SEM with an SE detector in high-vacuum mode at 1 kV acceleration voltage, observation mode (spot size 30). The working distance ranged between 1 mm and 5 mm. For quantification, automatic 6 × 6 mosaic tiled images at ×5k magnification were acquired at a random position with auto contrast/brightness using the microscope zig-zag function after manual adjustment of the focus and no further auto-focus. Pixel size was 3.96 nm. Images were 1280 × 960 pixels corresponding to 5078 × 3808 nm fields of view.