All-aqueous-processed Silk Fibroin/Chondroitin Sulfate Scaffolds

Chondroitin sulfate (CS) is a naturally derived bioactive macromolecule and has been used to improve the performance of silk fibroin (SF) biomaterials for soft tissue regeneration. However, it is still a challenge to use a chemical-free method to prepare water-insoluble SF/CS scaffolds. Here, a novel all-aqueous process was developed to prepare SF/CS scaffolds with controlled properties. Freezing-annealing treatment was used to induce silk I crystallization of SF to entrap CS macromolecules. It was found that the addition of CS did not prevent silk I crystallization of SF, even with a ratio as high as 10 % addition ratio. With increasing CS content, the water solubility of the scaffolds increased due to insufficient silk I crystals. The physicochemical properties of the scaffolds were evaluated, and the results showed that the water binding capacity and mechanical properties of the SF scaffolds can be effectively regulated by adding only less than 5 % CS content. This study provides a green strategy, including all-aqueous, low temperature, and without the use of toxic chemicals or solvents, to prepare bioactive SF/CS scaffolds for use in tissue engineering.