Study on Cast Membranes and Electrospun Nanofibers Made from Keratin/Fibroin Blends

Abstract

Keratin regenerated from wool and fibroin regenerated from silk were mixed in different proportions using formic acid as the common solvent. Both solutions were cast to obtain films and electrospun to produce nanofibers. Scanning electron microscopy investigation showed that, for all electrospun blends (except for 100% keratin where bead defects are present), the fiber diameter of the mats ranged from 900 (pure fibroin) to 160 nm (pure keratin). FTIR and DSC analysis showed that the secondary structure of the proteins was influenced by the blend ratios and the process used (casting or electrospinning). Prevalence of beta-sheet supramolecular structures was observed in the films, while proteins assembled in alpha-helix/random coil structures were observed in nanofibers. Higher solution viscosity, thinner filaments, and differences in the thermal and structural properties were observed for the 50/50 blend because of the enhanced interactions between the proteins.

Development of non-woven nanofibers of egg albumen-poly (vinyl alcohol) blends: influence of solution properties on morphology of nanofibers

“…Gelatin, fibrin, collagen and elastin are fibrous proteins that, at higher concentrations, have the ability to form nanofibers. 2,5,[11][12][13] However, protein alone may not always produce nanofibers with desired diameters (o100 nm) owing to either a mild or a complete lack of viscoelastic properties. Conversely, these nanofibers lack sufficiently strong mechanical, thermal and barrier properties, thereby limiting the scope of their applications.…”

Effect of freezing methods on the properties of lyophilized porous silk fibroin membranes

“…These results suggested the high molecular orientation and crystallinity in the fibroin proteins, since the SF with amorphous structure usually has a typical decline at 285 °C 19,20 . The DSC curves of the SF membranes (Figure 4) presented a strong endothermic peak for the wet sample around 100 °C, due to the evaporation of water 21 . All analyzed samples exhibit similar endothermic peaks at ca.…”

Keratin-based Nanofibres

“…lowest shear thinning onset). The resulting nanofibers were thin with respect to those produced with the other blend ratios, and the trend was repeated at different operating conditions (Zoccola et al, 2008). It had been supposed some interactions between keratin and fibroin promote the formation of entangled chain networks.…”

“…Moreover, synergic effects could enhance some properties: for instance, it was found that films cast from silk fibroin and keratin decreased blood coagulation compared with silk fibroin or keratin alone (Lee et al, 1998). Concerning the production of keratin/fibroin nanofibres by electrospinning, both silk fibroin and wool keratin can be dissolved in formic acid and mixed in several blending ratios Baek et al, 2007;Zoccola et al, 2008). Blend nanofibers rich in fibroin, show branched and flatten morphology characterized by a bimodal diameter distribution.…”

“…For electrospinning keratin should be blended with suitable polymers using common, volatile and easy to handle solvents. This is also recommended when mechanical performance is needed Katoh et al, 2004;Zoccola et al, 2008). This chapter describes the extraction of keratin from wool and electrospinning of keratin-based blends with high molecular weight polymers.…”