1. Methods Objectives Results Conclusions References
 The Novel Approach to Design a Bioengineered Scaffold for Corneal Regeneration, S.Sharareh Mahdavi 1*,Mohammad J. Abdekhodaie 1,Shohreh Mashayekhan 1, Keekyoung Kim2
Chemical and Petroleum Engineering ,Sharif university of technology ,Tehran ,Iran
School of engineering, The university of British Columbia , Kelowna , Canada *
Objectives
Results
Methods
The geometry of the cornea is printed at the same size of the human cornea (Fig1.). Although the hydrogel is printed layer by layer, more than 90% optical transparency is achieved. Moreover, 94% and 93% cell viability is observed for day 0 and day 7 respectively. Furthermore, a complete cell alignment is obtained in each layer after a week (Fig2.).
Using 3D bioprinting in tissue engineering is one of the newest approaches to regenerate the injured tissue. Natural biomaterials are known to be a perfect bioink for 3D bioprinting, since they are cyto-compatible and show less inflammatory response. The purpose of this study is to design a proper scaffold for corneal regeneration using gelatin methacrylate (GelMA) in 3D bioprinting technique. In this case, the geometry of the human cornea is designed and sliced by proper software and reflected to the bioink with visible light. 
Gelatin type A from porcine skin, Glycidyl methacrylate, Eosin Y disodium salt (Eosin Y), 4-(dimethylamino) pyridine (DMAP), and dimethyl sulfoxide (DMSO) are purchased from Sigma Aldrich. GelMA is prepared as follows: 5 g gelatin is dissolved in 50 ml DMSO with stirring at 50˚C. Then, DMAP is added to the mixture and dissolved. Subsequently, glycidyl methacrylate is added and the mixture is stirred for two days at 50 ˚C. The mixture is then dialyzed with reverse osmosis (RO) water at room temperature for five days. The water is changed every day and after dialysis, a freeze-dried sample is achieved via lyophilization. For preparing photocrosslinkable bioink, freeze-dried GelMA is dissolved with Eosin Y in PBS and stem cells are added to the solution. Subsequently, the geometry of the cornea is printed layer by layer exposing the bioink to visible light. The crosslinking time, the bioink volume and thickness of each layer is set to develop the normal round shape of the cornea. 
Conclusions
The results showed that GelMA is a proper bioink for 3D bioprinting the cornea geometry and the layer by layer bioprinting didn’t have negative effect on cell viability and proliferation.
Day 1
References
Day 7
Figure1. Printed cornea sample
Figure2. Cell viability in printed sample