Surface engineering of the retinal Bruch\u27s membrane for treatment of age-related macular degeneration

Age-related macular degeneration (AMD) causes loss of central visual function that ultimately leads to blindness. Prominent in older populations, AMD is the number one cause for blindness in the developed world. The decline in central visual function stems from degeneration of the macula. Early on, the degeneration of the macula is caused by changes in the retinal Bruch’s membrane (BM) that served as the basement membrane of the retinal pigment epithelium (RPE) layer. Loss of RPE layer patency leads to mal-nourishment of the photoreceptor layer leading to impairment of visual function. Currently treatments for AMD can only slow or arrest the disease progression, with very limited success in restoring visual function. AMD pathophysiological studies indicate that a way to restore vision is through transplant of donor cells. A major impediment to the success of this cell based therapy is the attachment and survival of RPE cells on diseased BM. This doctorate study was carried out as an effort to overcome this impediment. The proposed method is to surface engineer donor BM into a suitable scaffold to replace the diseased BM. For this purpose, the study is divided into two main focuses: a) the development of a surface patterning technique; and b) the development of a surface modification strategy. Since the BM is comprised of five distinct layers, the collagenous layer of the BM known as the inner collagenous layer (ICL) was selected as the surface to re-engineer. Meanwhile, Dip Pen Nanolithography (DPN) was studied as the method of choice for deposition of bioactive molecules. In conjunction, the ability of collagen binding peptides (CBP) to specifically bind to collagen fibers was investigated as a strategy to anchor bioactive molecules on the ICL surface. At the conclusion of this study, successful deposition of bioactive molecules on the ICL surface using DPN has been demonstrated. Furthermore, the addition of cell-attachment peptide sequence (RGDS) to the N-terminus of CBP was shown to increase the attachment and survival of ARPE-19 cells on the ICL surface. Based upon these findings, future studies may focus on directing the attachment and long-term survival of the cells