Abstract
Purpose: :
Human amniotic membrane (AM) is frequently used as a substrate for corneal surface reconstruction. Its disadvantages (e.g., reduced transparency and biomechanical strength, heterogeneity depending on donor) create the need for standardized alternatives. Keratin from hair or wool has been proposed as an appropriate material for producing films or cell cultivation scaffolds. The current study was carried out to develop transparent, stable and transferable films based on human hair keratin that support cellular adhesion and proliferation. The influence of various process parameters on the ultrastructure, biomechanical properties, light transmission and cell growth behavior of corneal epithelial cells on keratin film in comparison to AM were tested.
Methods: :
The films were engineered by a multi-step procedure including reductive keratin extraction, neutral and alkaline dialysis, casting on hydrophobic PET membrane, drying and a curing process. Modifications in film formation process were performed by varying protein and plasticizer concentration as well as curing temperature and duration. Keratin films were investigated by SDS-PAGE, SEM and X-ray analyses. Furthermore, swelling and water absorption of the films were studied, as were tensile strength and light transmission. Finally, the growth behavior of corneal epithelial cells on the keratin films and AM was estimated in proliferation studies.
Results: :
This novel film-forming process resulted in transparent films composed of nanoparticulate keratin structures. The film characteristics could be varied by changing the protein composition, adding softening agents or varying the curing temperature and duration. Based on these findings, an optimized protocol was developed. The films showed improved light transmission and biomechanical strength in comparison to AM. Furthermore, cell behavior on the films was similar to that found on AM.
Conclusions: :
Biopolymer films based on human hair keratin may represent a new, promising alternative for corneal surface reconstruction.
Keywords: cornea: epithelium • proliferation