The Retina in 3D

The field of tissue engineering is driven by the shortage of available organ donors and fears of organ rejection. Tissue engineering is the study of the growth of new connective tissues, or organs, on a tissue scaffold to produce new tissue that can be used for tissue replacement or repair. Tissue scaffolds are crucial for tissue engineering, because they can be engineered to mimic the properties of the target tissue and are used to guide the growth of new tissue. The research in our lab is focused on creating a retinal tissue scaffold that can be used to treat diseases such as glaucoma, which is a leading cause of blindness that affects over 3 million Americans. The disease is caused by the death of retinal ganglion cells. After they die, they are not able to grow back; however, the replacement of these cells through tissue implants could bring us closer to a cure for the disease.

Creating a tissue scaffold requires finding a material that can be used as a template for cells to grow and survive on. Hydrogels make excellent candidates for creating tissue scaffolds, because they are highly compatible with soft tissues. In addition, they are made up mostly of water, and the aqueous environment helps to protect the cells as well as facilitate cell transport and metabolite exchange.

retina

 

Figure 1 – A fluorescence image showing fluorescent-labeled retinal ganglion cells which were grown on a hydrogel and successfully implanted into a rat’s retina.

 

 

 

 

 

 

 

The image above demonstrates the previous work done in the lab by Dr. Erin Lavik of the Department of Chemical, Biochemical, and Environmental Engineering at the University of Maryland Baltimore County (UMBC). The image shows a hydrogel containing retinal ganglion cells that was implanted into a blind rat’s retina. The hydrogel was successfully able to replace the rat’s damaged retinal tissue with new retinal tissue. This work is promising, because it demonstrates that hydrogels can be incorporated into the body without being rejected and also have the potential to repair damaged tissues.

Taking it a step further, our current research is working to create a complete 3D tissue scaffold of the retina with hydrogels. The retina is an especially difficult tissue scaffold to create for the following reasons: (1) it has a specific, multi-layered structure; and (2) each layer is only 10 µm thick, which is about 10x thinner than a strand of hair. Thus far, we have successfully developed a technique to produce the hydrogel in virtually any desired shape at a thickness of approximately 50 µm. The combination of current and past work done in our lab will hopefully result in a 3D tissue scaffold of the retina, which will be a major step forward in cell replacement therapies.