Silk Fibroin Scaffolds as Biomaterials for 3D Mesenchymal Stromal Cells Cultures

Silk fibroin (SF), a protein-based fiber extracted from Bombyx mori cocoons, has recently emerged with great potential for the biomedical field to be used as a biomaterial processable in a variety of formats and applications, due to its natural characteristics. The aims of the present study were to characterize the structural properties of the SF scaffolds, in the format of porous sponges, and to investigate their feasibility to support the adhesion of mesenchymal stromal/stem cells isolated from human Wharton's jelly of the umbilical cord (WJ-MSC). Adhesion is a prerequisite for using the SF scaffold as biomaterial for supporting three-dimensional (3D) WJ-MSC cultures for several applications. The integration among micro-computed tomography, confocal analysis, and field emission scanning electron microscopy allowed carrying out a deep investigation based on quantitative morphological parameters and qualitative observations at high resolution. High levels of porosity, interconnection, and contact surface-volume ratio confirmed the appropriateness of the designed SF porous scaffolds as supports for cell cultures. WJ-MSC was demonstrated to be capable of adhering to and colonizing the SF scaffold applicable as a 3D cell culture system, of conducting in vitro experiments in a more controlled environment, and possibly of being used in tissue engineering, regenerative medicine, and applications in oncology.