Transparent silk/gelatin methacrylate (GelMA) fibrillar film for corneal regeneration.

Developing a transparent substitute with high water permeability and similar mechanical properties to cornea is one of the major challenge in corneal tissue engineering. Here, transparent hybrid films based on silk nanofibrils (SNF)/gelatin methacryloyl (GelMA) are introduced for cornea tissue engineering. The mechanical properties, transparency, degradation rate and swelling ratio of hybrid films could be tuned by modulation the volume ratio of SNF to GelMA. Among them, the optimal SNF/GelMA ratio of 30/70 shows high transparency with a light transmittance of more than 85% in the wet state, hydrophilicity and mechanical properties close to the natural corneal stroma. The elastic modulus of 36.2 ± 7 kPa, the tensile strength of 3.8 ± 1 MPa and the ability to absorb water up to 138 ± 27% are the features of this hybrid membrane. Moreover, incorporation of SNF upon 30 (v/v) % (30S/70G sample) significantly reduces the degradation rate of GelMA (upon 2 times) making it promising for cornea regeneration. Cell culture studies also prove the ability of SNF/GelMA films to support the attachment, spreading and proliferation of stromal cells, depending on the film composition. Noticeably, 30S/70G film significantly promotes cell metabolic activity (2 times) compared to SNF. In addition, 97 ± 2% of the area of this sample is covered with cells after 5 days of culture which is 8 times greater than that of SNF. In summary, the SNF/GelMA film with volume ratio of 30/70 presents desirable mechanical, optical and biological properties making it an attractive candidate for the regeneration of cornea.