“…Various bioengineering approaches have been attempted to fabricate corneal equivalence based on natural (e.g., collagen 1,4,5 , gelatin 6 , chitosan 7 , silk 8 , etc) or synthetic (e.g., poly (ethylene glycol) (PEG) 9 , poly (ε-caprolactone) (PCL) 10 , poly(lactic-co-glycolic acid) (PLGA) 1,11 , poly-hydroxyethylmethacrylate (PHEMA) 12 , etc) materials or the combination of natural and synthetic materials 1,4,13 by using the techniques of casting 14 , hydrogel 15 , 3D printing 16 , electrospinning 17,18 , and the combination of two or more of these processes 17 . Although these therapies and constructs have demonstrated acceptable mechanical properties and optical transmittance and can support corneal cells adhesion, migration, proliferation, and differentiation well, they fail to mimic the natural microenvironment of the native complex corneal tissue, and the most complicated part among the corneal tissue is the stroma.…”