A new method to prepare porous silk fibroin membranes suitable for tissue scaffolding applications

A new method to prepare porous silk fibroin (SF) membranes without dialysis is proposed. Silk fibers were degummed to remove sericin and the resultant fibroin was dissolved in a CaCl₂-CH₃CH₂OH-H₂O ternary solvent. Rather than undergoing dialysis, a fibroin salty solution was diluted in water and then submitted to a mechanical agitation that led to a phase separation through foam formation on the solution surface. This foam was continually collected and then compacted between plates to remove the excess of water. The membranes presented large pores with diameters of greater than 100 μm (as shown by scanning electron microscopy - SEM), porosity of 68% and water content of 91% w/w. X-ray diffraction (XRD) and infrared spectroscopy (FTIR-ATR) indicated that the membranes present SF in a β-sheet structure even before the ethanol treatment. A typical elastic deformation profile and degradation under temperature were observed using calorimetric analysis (DSC), thermal gravimetric analysis (TGA) and mechanical tests. As indicated by the in vitro cytotoxicity tests, these membranes present potential for use as scaffolds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009