Functional Nanocomposite Keratin-based Nanofibers by Colloid Electrospinning from Water Solutions

Multi-component organic/inorganic nanofibers were produced by electrospinning water solutions of a protein extracted from wool (i.e. keratin) containing colloids of titanium dioxide and metal silver. In order to improve electrospinnability poly(ethylene oxide) was added to the solutions. Colloidal stability was studied in depth to preserve as smaller as possible nanoparticle dimension in the electrospinning solutions. Resulting hybrid keratin-based nanofibers were made water insoluble by treatments at high temperature, expanding the range of applications of such a nano-material. In this way, it was also possible to wash out poly(ethylene oxide) from nanofibers maintaining a nanofibrous structure and small-sized porosity comparable to the as-spun materials. Finally, the functional properties of electrospun hybrid nanofibers were evaluated. Both antibacterial and photo-catalytic activities of titanium dioxide nanoparticles embedded into the nanofibers were quantified, as well as antibacterial property of nano-silver. The results demonstrate that nanoparticle functionalities are preserved in electrospun keratin nanofibers.