Chemico-Physical Characterization

Scaffold morphology was assessed by means of SEM (Tescan, Mira3XMU, CISRIC, University of Pavia) after graphite sputtering. The scaffolds were analyzed before and after the crosslinking procedure and after 6 days of hydration in distilled water. Nanofiber diameters and pores sizes were measured by image analysis software (DiameterJ plugin, Image J, NIH).

X-ray powder diffraction (XRPD) analysis was carried out using a diffractometer (X-Pert Pro model, Malven Panalytical, Italy) equipped with a solid-state detector (X-Celerator) and a spinning sample holder. The diffractogram patterns were recorded using random oriented mounts with CuKα radiation, operating at 45 kV and 40 mA, in the range 4–60◦ 2θ. The diffraction data were analyzed using the XPOWDER® software (www.xpowder.com).

Fourier-transform infrared spectroscopy (FT-IR) spectra were recorded using spectrophotometer (JASCO 6200) with a Ge ATR. All samples were analyzed from 400 to 4000 cm−<sup>1</sup> with a resolution of 0.25 cm−<sup>1</sup> and the results were processed with Spectra Manager v2 software.

Thermogravimetric analysis (TGA) (TGA-50H, Shimadzu, Kyoto, Japan) was performed using a vertical oven and a precision of 0.001 mg. Approximately 40 mg of each sample were placed in aluminum pans. The experiments were performed at the 30–950 ◦C range and using a 10 ◦C/min heating rate. Additionally, differential scanning calorimetry (DSC) analyses were performed (Mettler Toledo, Columbus, OH, USA) using aluminum crucibles, a 30–400 ◦C temperature range, at a heating rate of 10 ◦C/min. All the analyses were performed in atmospheric air.

High-resolution Transmission Electron Microscopy (TEM) was performed by means of an analytical electron microscope (AEM) (Titan G2 60–300, FEI Company, Thermo Fisher Scientific, Waltham, MA, USA) with a SUPER-X silicon-drift windowless energy dispersive X-ray spectroscopy detector. X-ray chemical element maps were also collected. The samples were directly deposited onto copper grids (300 mesh coated by formvar/carbon film, Agar Scientific, Italy).
