The cornea is responsible for adjusting arrival light. It has three main layers of epithelium, stroma, and endothelium. Stroma constitutes 90% of its thickness. Therefore, any genetically or nonhereditary stromal degeneration can lead into complete blindness. Therefore, regarding rejection and risk of infection of transplanted donor tissues, tissue engineering has become a promising approach for corneal stromal regeneration. Photocrosslinkable hydrogels draw scientists’ attention because of their fast cytocompatible polymerization. Therefore, gelatin-methacrylate (GelMA) is one of the promising alternatives for tissue regeneration using photocrosslinkable hydrogels. Wang et. al. showed GelMA is highly cytocompatible and simple or complex geometry can be provided by it. They also designed microstructure using laser beam within 10 seconds with more than 90% cell viability. However, one of its disadvantages is low mechanical properties and stiffness. In this study, we used visible light and 3D bioprinting technique to print corneal structure using the GelMA and Polyethylene glycol methacrylate (PEGDMA) hydrogel.

The 3D printer set up was designed using MATLAB software and it has three main parts: a projector, a water filter, and a syringe pump. The geometry of stromal cornea was designed based on corneal actual size. GelMA and PEGDMA were printed layer by layer using visible light and designed structure (GELPEG). The whole structure was also printed using GelMA hydrogel for comparing the physical properties.

As it was expected, PEGDMA improved the mechanical properties and degradation rate of the printed sample. However, the GelMA hydrogel had higher transparency and the written text was clearer under it.

The addition of PEGDMA enhanced the physical properties of the hydrogel and the structure was stiffer than the GelMA hydrogel.