Silk Fibroin-Grafted Glycidyl Methacrylate

Raw silk cocoons were cut into small pieces and degummed with 1% (w/v) Na₂CO₃ at a weight ratio of 1:50, boiled at 98 ± 2 °C for 30 min to remove sericin, and then washed with deionized water several times. Subsequently, the degummed silk was dried overnight at 60 °C in a hot air oven. We dissolved 10 grams of degummed silk in 100 mL of a mixture of CaCl₂/Ca(NO₃)₂/H₂O/EtOH (30/5/45/20 weight ratio) in a microwave (Samsung, MS23K3513AW, 800 W). In the grafting process, 0.490 mmol of GMA was added to the SF solution. The mixture was stirred at 300 rpm at 60 ± 2 °C for 1 h. The mixture was then dialyzed with deionized water using SnakeSkin dialysis tubing, with a molecular weight cutoff of 10 kDa for 3 days, and deionized water was replaced every 4 h to remove salts and non-reactions. After completion of the dialysis, the undissolved impurities were removed by centrifugation at 10,000 rpm at 4 °C for 20 min to eliminate silk aggregates as well as debris from the original cocoons. The mixture was frozen at −60 °C for 12 h and freeze-dried at −70 °C for 48 h. The freeze-dried SF-g-GMA was stored at room temperature in a desiccator until further use.