Optically transparent silk fibroin nanofiber paper maintaining native β-sheet secondary structure obtained by cyclic mechanical nanofibrillation process

Optically transparent fibroin nanofiber (FNF) paper was obtained without using binders by passing a fibroin suspension through a mechanical nanofibrillation process using a water-jet. The optical transmittance of the nanofiber paper increased with the number of passes through the water-jet and reached 79.3% and 80.3% of light at 600 nm after 15 and 30 passes, respectively. The fibroin of the transparent nanopaper remained fibrous with a native beta-sheet secondary structure. Therefore, the transparent nanopaper showed a high elastic modulus, high thermal durability, and low thermal expansion. This novel protein material, which can be fabricated without toxic chemicals or organic solvents, is bio-friendly and shows promise for new applications in biocompatible photonic devices.

Automated summary

Optically transparent fibroin nanofiber (FNF) paper was achieved by mechanical nanofibrillation without using binders, showing high optical transmittance and promising applications in biocompatible photonic devices.