Keratin-based antimicrobial textiles, films, and nanofibers

• Published in: Journal of materials chemistry. B, Materials for biology and medicine Vol. 1; no. 40; pp. 5505 - 5514
• Main Authors: Dickerson, Matthew B, Sierra, Alexandra A, Bedford, Nicholas M, Lyon, Wanda J, Gruner, William E, Mirau, Peter A, Naik, Rajesh R
• Format: Journal Article
• Language: English
• Published: England 28.10.2013
• Subjects: Bacillus; Escherichia; Staphylococcus
• ISSN: 2050-750X; 2050-7518
• DOI: 10.1039/c3tb20896f

The combination of appealing structural properties, biocompatibility, and the availability of renewable and inexpensive raw materials, make keratin-based materials attractive for a variety of applications. In this paper, we report on the antimicrobial functionalization of keratin-based materials, including wool cloth and regenerated cellulose/keratin composite films and nanofibers. The functionalization of these materials was accomplished utilizing a facile chlorination reaction that converts the nitrogen-bearing moieties of keratin into halamine compounds. Halamine-charged wool cloth exhibited rapid and potent bactericidal activity against several species of bacteria and induced up to a 5.3 log (i.e., 99.9995%) reduction in the colony forming units of Bacillus thuringiensis spores within 10 min. Keratin-containing composites were prepared by the spin coating and coaxial electrospinning of extracted/oxidized alpha-keratin and cellulose acetate (CA) solubilized in formic acid, followed by CA deacetylation. Regenerated cellulose/keratin materials chlorinated to display halamines were also effective in killing Escherichia coli and Staphylococcus aureus bacteria. Electrospun core/shell nanofibers engineered to maximize keratin-Cl surface area displayed higher activity against S. aureus than films composed of the same materials. The halamine-based antimicrobial functionalization methods demonstrated for keratin-based materials in this paper are anticipated to translate to other protein biopolymers of interest to the biomaterials community.