Preparation of translucent and flexible human hair protein films and their properties

We have developed novel procedures for preparing human hair protein films (Pre-cast and Post-cast methods). The light brown films obtained by these procedures were too fragile to apply to human skin. We found that the film was also formed when the hair proteins extracted by the Shindai method were directly exposed to the solution containing MgCl(2), CaCl(2), NaCl or KCl. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the surface of the novel protein films was smooth. The protein films mainly consist of alpha-keratins and matrix proteins. After drying, the films became translucent and flexible during folding, indicating the possibility that these protein films are useful for practical applications. Hence, we prepared gauze-coated protein films to reinforce their physical strength and tested the influence on human skin. A patch test showed that the protein films made from individual and multiple human hairs only slightly stimulated rubor and anthema, itching, drying, smarting and pain on the contact area of arm skin.