56. Regenerated Protein Fibers from Lysozyme

Amyloid proteins (lysozymes) found in egg white were regenerated into macro- and nanofibers using a wet-spinning approach [03Tsu, 11Mei]. Lysozyme was dissolved in 10 mM HCl and allowed to form nanofibers with diameters of 2.6 ± 0.7 nm and lengths in excess of 10 μm. To form macrofibers, the nanofibers were cross-linked with anionic polyelectrolyte gellan gum through interfibrillar interactions. Figure 56.1 shows images of the nanofibers and macrofibers obtained, and Table 56.1 provides a comparison of the properties of the fibers obtained after cross-linking to various extents. Cross-linking and increasing the concentration of the protein solution improved tensile properties as seen in Table 56.1. The tensile strength of the lysozyme fibers is considerably higher than that of the regenerated fibers produced from plant proteins but lower than that of natural Bombyx mori silk. When used for controlled release applications, a pH-triggered release of riboflavin molecules was obtained with 75 % of loaded drug released within 10 min at pH 7 compared to less than 5 % of the drug released at pH 2 suggesting that the fibers could be used for controlled drug release.