5th May 2017

First soft synthetic retina for the visually impaired

The first synthetic retina using soft biological tissues has been created by a student at the University of Oxford.



Credit: Oxford University

A synthetic, soft tissue retina developed by an Oxford University student could offer fresh hope to visually impaired people. Until now, all artificial retinal research has used only rigid, hard materials. However, new research by Vanessa Restrepo-Schild, a 24-year-old Dphil student and researcher at Oxford University's Department of Chemistry, is the first to successfully use biological, synthetic tissues, developed in a laboratory. The study could revolutionise the bionic implant industry and the development of new, less invasive technologies that more closely resemble human body tissues, helping to treat degenerative eye conditions.

Just as photography depends on camera pixels reacting to light, our vision relies on the retina performing the same function. The retina sits at the back of the human eye, and contains protein cells that convert light into electrical signals that travel through the nervous system, triggering a response from the brain, ultimately building a picture of the scene being viewed.

Restrepo-Schild led the team in developing a new synthetic, double layered retina that closely mimics the natural human retinal process. The retina replica consists of soft water droplets (hydrogels) and biological cell membrane proteins. Designed like a camera, the cells act as pixels, detecting and reacting to light to create a greyscale image. Restrepo-Schild explains: "The synthetic material can generate electrical signals, which stimulate the neurons at the back of our eye – just like the original retina."

The study, published in Scientific Reports, shows that unlike existing artificial retinal implants, the cell cultures are created from natural, biodegradable materials and do not contain foreign bodies or living entities. In this way, the implant is less invasive than a mechanical device, and is less likely to have an adverse reaction on the body. Miss Restrepo-Schild adds: "The human eye is incredibly sensitive, which is why foreign bodies like metal retinal implants can be so damaging – leading to inflammation and/or scarring. But a biological synthetic implant is soft and water based, so much more friendly to the eye environment."

Of the motivation behind her ground-breaking study, Miss Restrepo-Schild says: "I have always been fascinated by the human body, and want to prove that current technology could be used to replicate the function of human tissues, without having to actually use living cells.

"I have taken the principals behind vital bodily functions, e.g. our sense of hearing, touch and the ability to detect light, and replicated them in a laboratory environment with natural, synthetic components. I hope my research is the first step in a journey towards building technology that is soft and biodegradable instead of hard and wasteful."

Although at present the synthetic retina has only been tested in laboratory conditions, Miss Restrepo-Schild is keen to build on her initial work and explore potential uses with living tissues. This next step is vital in demonstrating how the material performs as a bionic implant.

Restrepo-Schild has filed a patent for the technology and the next phase of work will expand the replica's function to include recognising colours and potentially even shapes and symbols. Looking further ahead, the team will begin to include animal testing and then a series of clinical trials in humans.

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