Conformation transition of silk fibroin induced by blending hydroxypropyl methylcellulose

The blend membranes of silk fibroin (SF) and hydroxypropyl methylcellulose (HPMC) were made. The effect of HPMC on the conformation transition of silk fibroin membranes was analyzed by Fourier transform infrared spectrum, X-ray diffraction, and Differential scanning calorimetry. The results demonstrated that the content of blending HPMC had a great influence on the conformation of silk fibroin membranes. The conformational change from a random coil or Silk I to β-sheet structure occurred when blending 3%-10% HPMC and the β-sheet content was maximal when HPMC content was 7%. This result is due to the formation of intermolecular hydrogen bonds when some content HPMC was mixed with fibroin. The result of water-solubility showed the blend film was almost insoluble when HPMC content was 7%.