University of Sheffield researchers have developed a new method for producing membranes to help in the grafting of stem cells onto the eye, mimicking structural features of the eye itself. The technology has been designed to treat damage to the cornea, the transparent layer on the front of the eye, which is one of the major causes of blindness in the world.
Using a combination of techniques known as microstereolithography and electrospinning, the researchers are able to make a disc of biodegradable material that can be fixed over the cornea. The disc is loaded with stem cells that then multiply, allowing the body to heal the eye naturally.
“The disc has an outer ring containing pockets into which stem cells taken from the patient’s healthy eye can be placed,” explains EPSRC Fellow, Dr Ílida Ortega Asencio, from Sheffield’s Faculty of Engineering. “The material across the centre of the disc is thinner than the ring, so it will biodegrade more quickly allowing the stem cells to proliferate across the surface of the eye to repair the cornea.”
A key feature of the disc is that it contains niches or pockets to house and protect the stem cells, mirroring niches found around the rim of a healthy cornea. Standard treatments for corneal blindness are corneal transplants or grafting stem cells onto the eye using donor human amniotic membrane as a temporary carrier to deliver these cells to the eye. For some patients, the treatment can fail after a few years as the repaired eyes do not retain these stem cells, which are required to carry out on-going repair of the cornea.
Without this constant repair, thick white scar tissue forms across the cornea causing partial or complete sight loss. The researchers have designed the small pockets they have built into the membrane to help cells to group together and act as a useful reservoir of daughter cells so that a healthy population of stem cells can be retained in the eye.