The first synthetic retina made of soft materials has been developed by an Oxford University researcher, with potentially life-changing conditions for those with retinal conditions.
Vanessa Restrepo-Schild, a doctoral student and researcher at the Department of Chemistry, developed the synthetic retina made of water-based materials, the first of its kind.
Her study ‘Light-Patterned Current Generation in a Droplet Bilayer Array’ was published last month in the journal Scientific Reports. The retina is a composition of cells at the back of the eye.
Photoreceptors are cells which convert light into electrical signals, before they are communicated into the brain for further processing. It forms the first step in creating the picture of the scene around us is processing in the photoreceptors in the retina—effectively allowing us to see.
In degenerative retinal conditions, the photoreceptors are impaired but the rest of the eye is relatively healthy, so only the first step in the vision process is disrupted. In these cases, although light can enter the eye, it can not be transformed into images.
To simulate photoreceptors, the synthetic retina developed by Restrepo-Schild contains 16 droplets arranged in hydrogels and bacteriorhodopsin from microorganisms. When patterns of light are shown to the display, currents are generated at each biopixel, and recorded simultaneously in order to represent the original pattern of light. The system works like a camera, with cells detecting and reacting to light to create a greyscale image.
A University press release said: “The synthetic material can generate electrical signals, which might stimulate the neurons at the back of our eye just like the original retina.”
The journal article notes that this research is following 20 years of research work on bioelectrical imaging devices using bacteriorhodopsin. However, the only currently available synthetic retinas are made of hard materials such as silicon, which are much less comfortable and convenient.
The material of the implant is unique to the research. Her synthetic retina contains natural, biodegradable materials, and does not contain any foreign bodies or living entities. Therefore, it is more similar to human body tissues and is less likely to be rejected by a human body.
The new synthetic retina is a single device in which the light sensor and current generator are integrated, presumably with no need for a camera or antenna.
According to Restrepo-Schild: “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.”
Restrepo-Schild added that her motivation was not limited to just the eye, saying: “I want to take the principles 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.”
The next step in the process is to see how this synthetic retina will perform as a bionic implant, and in the future, testing on animals and then humans, to one day improve the lives of those who can not see.
