An Australian researcher at the University of Sydney has developed an electronic, 3-D printed neural interface that can act as an artificial retina. The device could eventually restore visual function in patients with spinal cord injuries or neurodegenerative diseases that cause impaired vision.

The device is a joint project involving two departments: the Australian Centre for Microscopy & Microanalysis and the School of Aerospace, Mechanical and Mechatronic Engineering. Dr. Matthew Griffith and his research team, seeking to replicate the thin tissue at the back of the eye known as the retina, built the device using carbon-based semiconductors. The multi-colored semiconductors absorb light like a natural retina, causing neurons to transmit visual signals to the brain.

Spinal injuries can disrupt the connection between the retina and the sensory neurons involved in vision or cause the neurons to misfire, as can Parkinson’s and other neurodegenerative diseases. Age-related macular degeneration and other conditions that cause damage to the retina also interrupt the neural path to the brain. The new artificial retina could restore the connection between the eye and the brain and retrain misfiring neurons to function correctly.

Printed using standard commercial equipment, the device could become a cost-effective treatment option. Using carbon, a foundational element of human cells, the researchers created a softer, more flexible device than existing silicon and metal retinas. Most significantly, the University of Sydney retina is powered by light alone. 

Biological growth factors added to the flexible surface on which the semiconductors are printed trigger cell regeneration when in contact with damaged neurons. As they regrow, the neurons connect to the device, restoring the eye’s ability to transform light into sensory information for the brain to interpret. The team tested the device in a petri dish using neuronal cells from mice, confirming the regenerated neurons were functioning by measuring their electrical activity.

The team believes their neural interface could provide better visual acuity than other solutions, such as replicating the entire eye or parts of the brain. The University of Sydney device is also simpler and less costly to manufacture. In addition to the enormous potential the neural interface has for restoring vision, the technology could serve as a breakthrough prototype for interfaces that restore other sensory functions, such as hearing. The Sydney engineers will pair up with University of Newcastle neurobiologists to develop more precisely targeted neural regeneration in the next phase.