Effect of Silk Fibroin Aqueous Solution on Structure and Properties of Regenerated Porous Scaffold Materials Using Freeze-Thaw Method

Three typical solvent systems, calcium chloride-ethanol-water, lithium bromide-water, and calcium chloride-formic acid, were employed to dissolve degummed silk fibers. The resulting silk fibroin solutions were subsequently subjected to dialysis, filtration, and concentration processes to obtain three distinct silk fibroin aqueous solutions. Porous scaffolds were then fabricated from each solution using the freeze-thaw method. The morphology, porosity, structure, thermal stability, and mechanical properties of the resulting scaffolds were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical testing. The results indicated that the preparation methods of the three silk fibroin aqueous solutions exerted only a minor influence on the structure and properties of the freeze-thaw-derived porous scaffolds. All scaffolds exhibited interconnected porous architectures and a stable Silk I conformation. However, the scaffold derived from the calcium chloride-formic acid-based silk fibroin solution showed a higher β-sheet content and superior compressive mechanical properties.