Carbon tape

The samples were analyzed on FeSEM Auriga (Crossbeam 540, ZEISS, Oberkochen, Germany) for obtaining SEM images at 5 kV at magnifications of 500 and 2000 times. For EDS analysis, a JSM-IT200 (JEOL, Tokyo, Japan) microscope at 20 kV at a magnification of 2000 times was used. The samples (sonic, Elpol, HT) were attached onto a carbon tape (Agar scientific, Stansted, UK) before analysis.

A schematic representation of how the clots were sectioned for each measurement is presented in the Supplementary information (Supplementary Fig. 5). Both static and flow clots were sectioned into the head, middle and tail sections and only the middle sections were used for each measurement. Two clots per flow condition were prepared for SEM imaging, with each clot being imaged at high magnification (horizontal field width of 20.7 μm and a pixel size of 7 nm) in at least 5 different, randomly selected regions. To prepare the clots for SEM imaging, they were first washed in cacodylate buffer for 30 min, fixed in 2% glutaraldehyde for 2 h, dehydrated in an increasing concentration of ethanol from 30% to 100% in series, and dried in hexamethyldisilane (HDMS). The dried samples were then secured on aluminum mounting pins (Agar Scientific) by carbon tape (Agar Scientific) and finally sputter-coated with gold (Sputter Coater E5000) to achieve a layer of ~15 nm covering the samples. The SEM images were acquired with a Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) (Helios NanoLab 650). The backscattered ions were detected with an Everhart-Thornley detector at a voltage of 10 kV, with a tilt of 0.0, a dwell time of 3 μs and a working distance of 4.46 mm. The final images were 20.8 × 14.8 μm with 3072 × 2188 pixels.

The qualitative assessment of VSP morphology after mixing with AF and the qualitative analysis of AF particle dispersion in the composites were carried out with scanning electron microscopy investigations (SEM) (Supra 25, Zeiss, Berlin, Germany). For the powder samples, they were taken from randomly selected locations and placed on a carbon tape (Agar Scientific, London, UK). Filler dispersion in the polymerized composites was analyzed in cross sections obtained by breaking the sample previously cut to 1/3 of its thickness in liquid nitrogen. The samples were dried for 2 h at a temperature of 40 ± 1 °C in a desiccator containing silica gel freshly dried at 130 °C for 4 h. The samples were sputtered with gold. The accelerating voltage was 1 to 5 kV.

An optical micrometer (Keyence LS-7010MR laser with Keyence LS-7601 monitor, Milton Keynes, United Kingdom) was used to measure suture diameter by averaging five measurements, which was then converted to United States Pharmacopeia (USP) suture sizing standardization. Scanning electron microscopy (SEM) was used to measure fiber diameter. Suture materials measuring 2–3 cm were cut and mounted on aluminum stubs (Agar Scientific, Essex, United Kingdom) using carbon tape (Agar Scientific).
These stubs were coated with gold for 120 s using a SC7620 Mini Sputter Coater System (Quorum Technologies Ltd, Laughton, United Kingdom). SEM images were acquired using an EVO LS15 VP-SEM (Carl Zeiss, EVO LS15, Oberkochen, Germany) in high vacuum mode to examine suture morphology. Fiber diameter was measured from SEM images using ImageJ software (National Institutes of Health, Bethesda, MD). For each experimental condition, 3 samples were imaged and 10 measurements per image were captured at magnifications between 200 × and 1000 × .