Scheme 1.

(A) A promising strategy for using recycled silk waste to take the place of silk cocoons from natural sources to prepare silk-based hydrogels as protein/peptide carriers. (B) Procedure to obtain silk fibroin aqueous solution. The raw silk textile yarns were degummed by the secondary boiling method with sodium carbonate solution. The obtained degummed silk was dissolved in 9.3 mol/L lithium bromide solution, followed by a series of processes such as dialysis, filtration, and concentration determination to prepare a silk fibroin aqueous solution with a concentration of 30 mg/mL. (C) The sol-gel transformation process at pH 7.4 at a temperature of 37 °C.