The nanomechanical role of melanin granules in the retinal pigment epithelium

Retinal pigment epithelium (RPE) is a single layer of cells that contains the pigment melanin. RPE plays an important role as a blood-retinal barrier (BRB) that separates the retina from the choroid. It is believed that certain age-related diseases of the retina, such as mechanical breakdown of the BRB or age-related macular degeneration begin as a result of pathological changes in the RPE. Here, we show that melanin granules are responsible for high stiffness of RPE cells, which helps in sustaining mechanical integrity of the BRB tissue.283