First liquid retina prosthesis developed to counteract damage from degenerative diseases

Written by Heather Jones (Future Science Group)

Researchers at the Italian Institute of Technology (IIT; Genoa, Italy) have applied nanotechnology to the development of the first liquid retina prosthesis – an aqueous suspension of photoactive nanoparticles that replace damaged photoreceptors.

The study has been published in Nature Nanotechnology and describes the potential of this novel technology to counteract the effects of diseases such as retinitis pigmentosa and age-related macular degeneration, which cause the degeneration of photoreceptors of the retina, resulting in blindness.

Building on the planar artificial retinal model, developed by the same team at IIT in 2017, this ‘second generation’ artificial retina is biomimetic, offers high spatial resolution and consists of an aqueous component in which photoactive polymeric nanoparticles can replace the damaged photoreceptors.

Unlike other existing approaches, the novel liquid nature of this prosthesis ensures quicker, more effective and less traumatic surgery. The treatment consists of microinjections of nanoparticles directly under the retina, where they replace degenerated photoreceptors.

“In this research we have applied nanotechnology to medicine,” commented Guglielmo Lanzani (IIT). “In particular in our labs we have realized polymer nanoparticles that behave like tiny photovoltaic cells, based on carbon and hydrogen, fundamental components of the biochemistry of life.”

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Using rats to test their novel method, the researchers demonstrated that the natural light stimulation of nanoparticles cause the activation of retinal neurons, therefore mimicking the performance of healthy photoreceptors.

“Our experimental results highlight the potential relevance of nanomaterials in the development of second-generation retinal prostheses to treat degenerative retinal blindness, and represents a major step forward. The creation of a liquid artificial retinal implant has great potential to ensure a wide-field vision and high-resolution vision, explained Fabio Benfenati (IIT), who also added that enclosing the photoactive polymers in particles that are smaller than the photoreceptors increases the active surface of interaction with the retinal neurons and allows easier coverage of the entire retinal surface and the scaling of the photoactivation at the level of a single photoreceptor.

The team believes that this technique could represent a viable alternative to the methods currently used to restore the photoreceptive capacity of retinal neurons, while preserving their spatial resolution.

“The surgical procedure for the subretinal injection of photoactive nanoparticles is minimally invasive and potentially replicable over time, unlike planar retinal prostheses,” added Grazia Pertile (IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy). “At the same time maintaining the advantages of polymeric prosthesis, which is naturally sensitive to the light entering the eye and does not require glasses, cameras or external energy sources.”

They hope to take this novel method to clinical trials, and anticipate further developments in the application of neuroscience to medicine.

Sources: Maya-Vetencourt JF, Manfredi G, Mete M et al. Subretinally injected semiconducting polymer nanoparticles rescue vision in a rat model of retinal dystrophy. Nat. Nanotechnol. doi:10.1038/s41565-020-0696-3 (2020); www.eurekalert.org/pub_releases/2020-06/iidt-nat062920.php