4200 spectrometer

Fourier transform infrared (FT-IR) spectra were recorded using a JASCO 4200 spectrometer using with a Specac Golden Gate attenuated total reflectance (ATR) device in the 4000–600 cm⁻¹ wavenumber region, with a resolution of 4 cm⁻¹ and an accumulation of 200 spectra. Casein, H1P1C0 synthetic hydrogel, and nanohydroxyapatite (from Sigma) were used as control samples.

The in vitro mineralization capacity of the CS–FG3 printed scaffolds was investigated based on the methods described in the literature data [33 (link),34 (link),35 (link)]. Briefly, the scaffolds were immersed in individual test vials containing SBF at 37 °C, using a solid/liquid ratio of 0.5 mg mL⁻¹ in the vials. After 7 and 14 days, respectively, the printed scaffolds were taken out and carefully washed to avoid the remaining soluble salts from the SBF. The results of the mineralization test were assessed morpho- and microstructurally by SEM using the method described in Section 2.2.4. The elemental mapping monitored the formation of a new mineral phase, while the ratio Ca/P was measured. In addition, Fourier transform infrared spectroscopy (FTIR) analysis was performed on the 3D printed scaffolds, before and after incubation in SBF for 7 and 14 days. Nano-hydroxyapatite, HAp, (Sigma Aldrich) was used as a control. A JASCO 4200 spectrometer equipped with a Specac Golden Gate attenuated total reflectance (ATR) device was used, and the spectra were registered in the wavenumber regions of 4000–600 cm⁻¹ at a resolution of 4 cm⁻¹.