Bio-composite keratin films from wool fibrillation

Wool and hair can be regarded as bio-composite keratin-based fibres made up of spindle shaped cortical cells oriented along the fibre, embedded in an amorphous protein matrix. This natural composite structure has been exploited to prepare cheap and easy keratin-based films. Wool was submitted to alkali treatment, rinse, and ultrasonic disruption of its hierarchic assembly, obtaining a suspension of cortical cells in a protein aqueous solution that was transformed into films by cold casting. Preliminary investigation showed the bio-composite nature of the films, with randomly oriented cortical cells embedded in the protein matrix. Structural characterization revealed the presence of predominantly -sheet secondary structure due to lanthionine and lysino-alanine covalent cross-links. Bio-composite keratin films are transparent and show good tensile strength and thermal stability, high moisture regain and swelling, but are fragile in ambient condition like films of reduced keratin reported in literature. Further characterization and improvement should candidate bio-composite keratin films from wool fibrillation as easy and cheap materials for biotechnology applications.