Bioprinted Membranes for Corneal Tissue Engineering: A Review.

Corneal transplantation is considered a convenient strategy for various types of corneal disease needs. Even though it has been applied as a suitable solution for most corneal disorders, patients still face several issues due to a lack of healthy donor corneas, and rejection is another unknown risk of corneal transplant tissue. Corneal tissue engineering (CTE) has gained significant consideration as an efficient approach to developing tissue-engineered scaffolds for corneal healing and regeneration. Several approaches are tested to develop a substrate with equal transmittance and mechanical properties to improve the regeneration of cornea tissue. In this regard, bioprinted scaffolds have recently received sufficient attention in simulating corneal structure, owing to their spectacular spatial control which produces a three-cell-loaded-dimensional corneal structure. In this review, the anatomy and function of different layers of corneal tissue are highlighted, and then the potential of the 3D bioprinting technique for promoting corneal regeneration is also discussed.

Corneal stromal regeneration by hybrid oriented poly (ε-caprolactone)/lyophilized silk fibroin electrospun scaffold.

Applying biological macromolecule like silk fibroin (SF) is a promising material for corneal tissue engineering. However, designing an appropriate tissue-like construct to compensate the shortages of traditional routes are still challenging. SF besides possessing biocompatibility and transparency, the biomaterial should be mechanically strong. In the present study, a hybrid scaffold composed of poly-ε-caprolactone (PCL)-silk fibroin (SF) is fabricated through electro spinning technique. The aligned and non-aligned PCL-SF scaffolds with various weight ratios are fabricated. The results reveal that the addition of SF yields the scaffolds with more uniform and aligned structure. The ultimate tensile strength and Young's modulus of aligned and non-aligned PCL-SF (60:40 and 50:50) fibers are in an acceptable range for cornea applications. It is noteworthy that the aligned PCL-SF (60:40 and 50:50) scaffolds have more transparency, hydrophilicity, water uptake, and in vitro degradation rate than the other scaffolds. The cell compatibility results show that human stromal keratocyte cells are attached and proliferated on the aligned and non-aligned PCL-SF scaffolds. The overall results recommend that PCL-SF (60:40 and 50:50) scaffolds have a great potential for human corneal stromal regeneration.