Silk Film Stiffness Modulates Corneal Epithelial Cell Mechanosignaling

Silk fibroin films are excellent candidate biomaterials for corneal tissue engineering due to their optical transparency, biocompatibility, and mechanical strength. Their tunable chemical and mechanical properties open the possibility of engineering cellular microenvironments that can both mimic native corneal tissue and provide stimuli to actively promote wound regeneration. While silk film mechanical properties, such as surface topography, have demonstrated the ability to control corneal epithelial cell wound regenerating behavior, few studies have explored the stiffness tunability of these films and its cellular effects. Cells are known actively sense the stiffness of their surroundings and processes such as cell adhesion, migration, proliferation, and expression of stem markers can be strongly influenced by matrix stiffness. This study develops technical solutions that allow for both the fabrication of films with stiffnesses similar to corneal tissue and also for their characterization in an aqueous, native-like environment at a scale relevant to cellular forces. Physiological evidence demonstrates that corneal epithelial cells are mechanosensitive to films of different stiffnesses and show that cell spreading, cytoskeletal tension, and molecular mechanotransducer localization are associated with film stiffness. These results indicate that silk film stiffness can be used to regulate cell behavior for the purposes of ocular surface repair.