Reconstruction of a Hard Connective Tissue Utilizing a Pressed Silk Sheet and Type-I Collagen as the Scaffold for Fibroblasts

A pressed silk sheet is a new biomaterial composed of a network of numerous cocoon filaments and having excellent mechanical strength and shape stability compared to a cotton-gauze sheet. To reconstruct a hard connective tissue using the silk sheet and type-I collagen as the scaffold for fibroblasts, three different three-dimensional floating culture systems were designed. “On sheet” system: fibroblasts were seeded on the silk sheet coated with collagen and the cell-attached sheet was cultured. “In gel” system: fibroblasts and the silk sheet were co-embedded in a collagen gel and the gel was cultured. “On vitrigel” system: fibroblasts were seeded on both sides of a collagen vitrigel involving the silk sheet and the vitrigel was cultured. The fibroblasts in all culture systems grew and formed disk-shaped connective tissue models involving the silk sheet by 14 days of culture. The “on sheet” and “on vitrigel” models retained a maximum elastic load of about 23 kgf and an ultimate tensile load of about 3.6 kg...