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Developing a 3D Retinal Tissue Scaffold Using PEG-Based Hydrogels – Kathy Barron

REU student Kathy Barron (center) working in the laboratory with her faculty mentor Prof. Erin Lavik (left) and fellow UMBC student Adam May (right).

Currently, there is a need for a better method of studying the complex groups of individual cells that compose our central nervous system. Standard in vitro cell culture methods are 2D; however, the cells in our body interact with each other in a 3D environment. Therefore, 2D cell culture methods do not provide an accurate representation of how neurons interact in vivo. I am working under Prof. Jennie Leach and Prof. Erin Lavik this summer to develop a method to create a 3D tissue scaffold of the retina with poly(ethylene glycol) (PEG)-based hydrogels. The study of retinal progenitor cells in a 3D tissue scaffold will provide further insight for engineering neural tissue for cell-replacement therapies following injuries and many other applications.

A schematic of the hydrogel formation is presented in the figure below. The hydrogel forms via a Michael-type addition of PEG-diester-dithiol onto four-arm PEG vinyl sulfone (PEG-VS).kathybpic

My undergraduate partner, Adam Day, and I are experimenting with different methods to produce a PEG-based hydrogel with the same shape and thickness of retinal tissue. Once the PEG hydrogel has the correct shape and thickness, we will then demonstrate that multiple layers can be laid on top of each other to produce the dome shape of the retina. Another challenge will be incorporating poly(L-lysine) into the hydrogel, so that the different types of retinal cells can be grown on each layer in a way that will allow the cells of the different layers to interact and form a complex intercellular network that would mimic the intercellular network of the retina in vivo.

Another project that I am involved in is focused on comparing the aggregation of the amyloid beta protein on a neural cell line of SY5Y cells in 2D and 3D cell cultures. Amyloid Beta (Aβ) is a small 4-5 kDa, negatively charged protein believed to be a causative agent in the progression of neuronal death in Alzheimer’s disease. Similar to the first project, a 3D cell culture model is expected to produce a more accurate representation of how the Aβ oligomers aggregate in neural tissue compared to 2D cultures. It is hypothesized that the 3D environment will be more stable for the Aβ oligomers than the 2D environment, resulting in a lower toxicity. This research will be important in determining the Aβ aggregation mechanisms and cytotoxicity in order to gain new insight on possible treatment targets and drug testing.