The optical properties of regenerated silk fibroin films obtained from different sources

• Published in: Applied physics letters Vol. 111; no. 10
• Main Authors: Perotto, Giovanni, Zhang, Yuji, Naskar, Deboki, Patel, Nereus, Kaplan, David L., Kundu, Subhas C., Omenetto, Fiorenzo G.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 04-09-2017
• Subjects: Absorptivity; Applied physics; Moisture content; Molecular weight; Optical materials; Optical properties; Proteins; Refractivity; Silk; Silk fibroin
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4998950

Silk fibroin possesses unique properties for bio-functional optical interfaces and has been attracting increasing interest as an optical material. Here, we report on the refractive index and absorption coefficient of silk fibroin extracted from Bombyx mori, Antheraea mylitta, Samia ricini, and Antheraea assamensis. The influence of protein molecular weight, residual water content, and crystallinity on refractive index was investigated. The parameters for the Cauchy dispersion law and Urbach absorption were determined for each of the silk fibroins. By exploiting the differences in refractive index between the different fibroins, an all-protein slab waveguide was fabricated.