Large‐area thin films of silk fibroin prepared by two methods with formic acid as solvent and glycerol as plasticizer

Abstract

AbstractThis article reports on an evaluation of the physical, chemical, thermal, morphological, and thermomechanical behavior of silk fibroin (SF) films conducted by a casting process with formic acid as solvent. Thin films of SF with and without glycerol were produced by two different methods, namely M1, from degummed SF, and M2, after degumming, dissolution, dialysis, centrifuge, and freeze‐drying of SF. According to the results, those fabricated by M1 are thinner and the addition of glycerol increased their thickness. All films showed high‐surface area of approximately 1033 cm2, good transparency, flexibility, absence of bubbles, hydrophilic characteristics, and high‐thermal stability. They displayed a predominantly crystalline structure, no heat‐induced crystallization, and spontaneous formation of β‐sheet, favored by a chemical treatment with ethanol and the plasticization with glycerol. Their morphology was dependent on the production method adopted, and the nanofibril structure of SF was kept in the films obtained by M1. The films proved viable for the production of scaffolds for tissue engineering due to their adequate chemical, physical, and thermomechanical properties for this purpose. The preparation methods adopted enabled the regulation of both the structure and the material properties of SF films, and generated films of large dimensions and able for use in the treatment of patients with extensive burns on the body.