Preparation of Silk-Fibroin Nanofiber Film with Native β-Sheet Structure via a Never Dried-Simple Grinding Treatment

Abstract

A nonregenerated silk-fibroin nanofiber film (FNF) was prepared from silk cocoon via a simple watergrinding treatment in a never-dried state and paper-making process after sericins were removed. Fibers 150‒ 200 nm in width were observed in the atomic force microscopy micrographs of the surface of the films,confirming that fine nanofibers were successfully obtained by the grinding treatment. Moreover, the prepared FNF maintained its silk β-sheet structure. Conventional regenerated fibroin films were also prepared for comparison of their morphological, mechanical, and thermal properties with those of the nonregenerated FNF. The elastic modulus of the nonregenerated FNF was higher than those of the conventional regenerated fibroin films. Moreover, the nonregenerated FNF also exhibited superior thermal durability. The native silk β-sheet structure of the FNF should be useful in the development of high-performance silk-based materials.