Rapid formation of flexible silk fibroin gel-like films

Flexible silk fibroin gel-like films with microporous morphology were prepared from B. mori silk fibroin fibers directly solubilized in formic acid/CaCl2 solvent. These films were characterized by several analysis techniques to determine the structure and properties of films. The pore size of gel-like films can be adjusted through SF concentration and Ca ions concentration. The controllable pore size in gel-like films was grew from 35 mu m to 100 mu m under the increase of fibroin concentration from 1.0 wt % to 8.0 wt %. At the same time, the water content of silk fibroin gel-like film decreased from 83.5 +/- 3.4% to 68.2 +/- 2.6%. With increasing Ca ions contents from 2.0 wt % to 10.0 wt % in dissolution process, the pore size and water content of silk fibroin gel-like films grew larger, especially its water content values reached 86.2 +/- 4.0% at 10.0 wt % Ca ions concentration. At wet condition, the gel-like film with beta-sheet structure showed higher breaking stress (4.26 +/- 0.31 MPa) and elongation (45.45 +/- 15.79%) at 8.0 wt % concentration. With the preparation method, the membrane is hydrophilic and the pore size is adjustable, which contributes to high toughness and favorable cell growth environment, suggesting that these silk fibroin gel-like films can be a potential candidate scaffold for biomedical applications, such as wound dressing, facial mask, contact lenses, etc. (C) 2014 Wiley Periodicals, Inc.