Publication Date

2013-05-07

Availability

Embargoed

Embargo Period

2015-05-07

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biomedical Engineering (Engineering)

Date of Defense

2013-05-01

First Committee Member

Ozcan Ozdamar

Second Committee Member

Jeffrey Goldberg

Third Committee Member

Herman Cheung

Fourth Committee Member

Fotios Andreopoulos

Abstract

Patients with diseases that lead to the loss of the cells of their outer retina, such as AMD and retinitis pigmentosa, suffer from an irreversible loss of vision. Since the body has no mechanism to restore the structure or function of these cells, could photoreceptors be transplanted to restore function? Several groups have attempted transplantations, but were faced with the challenges of low retention and inefficient delivery. Also, a limitation of photoreceptor research is their poor survival in culture due to their dependence on RPE. We purpose that a two-layered biodegradable polymer scaffold that serves as support and a permeable barrier between photoreceptors and RPE could provide support and enhance photoreceptor integration at the target site. This type of system will increase the survival of the photoreceptors by nurturing their dependence on RPE. Also, this scaffold will increase the efficiency of cell delivery by increasing the availability of the photoreceptors and therefore their chances of integration at the desired site. An electrospun scaffold was chosen for this application because a permeable scaffold can support cell retention, act as a barrier, while also allowing the two cell types to interact. This novel co-delivery was possible because we electrospun polylactic acid fibers on top of living RPE cells and seeded photoreceptors on top of the fibers. We used scanning electron microscopy, a Live/Dead cell assay, and immunohistochemistry to prove our hypothesis that it is possible to electrospin PLA scaffolds with consistent fiber diameters on top of living RPE cells, the cells are able to recover and display the same viability as control samples, and the scaffolds provide the support necessary for the seeded photoreceptors to remain separated and above the RPE layer.

Keywords

scaffold; retina; RPE; photoreceptors; electrospin

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