Keratin-based nanofibers with antibacterial and photo-catalytic activities

Multi-component organic/inorganic nanofibers were produced by electrospinning water solutions of keratin extracted from wool containing nanosols of titanium dioxide or metal silver. The resulting hybrid keratin-based nanofibers were made insoluble to water by treatments at high temperature. Nanofibers were observed by SEM before and after the heat treatments, and after the contact with water. Energy Dispersive X-ray analysis was performed with the aim of confirm the presence of inorganic nanoparticles. Finally, the functional properties (antibacterial property and photo-catalytic activity) of the nanoparticles embedded into the electrospun nanofibers were quantified on treated samples. The TiO2 reactivity was tested in both cases under UV light irradiation. Antibacterial tests were carried out using E. coli following the ATCC 100 Test Method on nanofibers treated with silver or TiO2. Both electrospun hybrid nanofibers showed excellent antibacterial properties confirming that the nanoparticles can exert their functions even if they are embedded in keratin nanofibers. Photocatalytic tests based on model reaction of Rhodamine B dye degradation showed promising photocatalytic property for the hybrid TiO2/keratin electrospun nanofibers. The results demonstrated that electrospun keratin nanofibers doped with active nanophases preserve nanoparticle properties, allowing the design of highly versatile hybrid multifunctional media.