The first liquid retina prosthesis

Research at IIT-Istituto Italiano di Tecnologia (Italian Institute of Technology) has led to the revolutionary development of an artificial liquid retinal prosthesis to counteract the effects of diseases such as retinitis pigmentosa and age-related macular degeneration that cause progressive degeneration of the photoreceptors of the retina, resulting in blindness. The study has been published in Nanotechnology nature.

The study represents the state of the art in retinal prostheses and is an evolution of the flat artificial retina model developed by the same team in 2017 and based on organic semiconductor materials (Natural materials 2017, 16: 681-689).

The ‘second generation’ artificial retina is biomimetic, offers high spatial resolution, and consists of an aqueous component in which photoactive polymeric nanoparticles are suspended (the size of which is 350 nanometers, therefore approximately 1/100 the diameter of a hair), and will replace damaged photoreceptors.

The experimental results show that the stimulation of natural light by nanoparticles, in fact, causes the activation of retinal neurons free of degeneration, thus mimicking the functioning of photoreceptors in healthy subjects.

Compared to other existing approaches, the new liquid nature of the prosthesis ensures rapid and less traumatic surgery consisting of micro-injections of nanoparticles directly below the retina, where they remain trapped and replace degenerate photoreceptors; This method also guarantees greater effectiveness.

The data collected also shows that the innovative experimental technique represents a valid alternative to the methods used to date to restore the photoreceptive capacity of retinal neurons while preserving their spatial resolution, laying a solid foundation for future human clinical trials. Furthermore, the development of these photosensitive nanomaterials opens the way to new future applications in neuroscience and medicine.

“Our experimental results highlight the potential relevance of nanomaterials in the development of second-generation retinal prostheses to treat degenerative retinal blindness, and it represents a great step forward,” said Fabio Benfenati. “Creating a liquid artificial retinal implant has great potential to ensure wide-field vision and high-resolution vision. Enclosing photoactive polymers in particles that are smaller than photoreceptors increases the active surface area for interaction with neurons. retinal, and allows easy coverage of the entire retina surface and scaling of photoactivation to the level of a single photoreceptor. “

“In this research we have applied nanotechnology to medicine,” concludes Guglielmo Lanzani. “In particular in our laboratories, we have made polymer nanoparticles that behave like small photovoltaic cells, based on carbon and hydrogen, fundamental components of the biochemistry of life. Once injected into the retina, these nanoparticles form small aggregates whose size is comparable to that of neurons, which effectively behave like photoreceptors. “

“The surgical procedure for subretinal injection of photoactive nanoparticles is minimally invasive and potentially replicable over time, unlike flat retinal prostheses,” adds Grazia Pertile, director of the Ophthalmology Operative Unit at IRCCS Ospedale Sacro Cuore Don Calabria. “At the same time, it maintains the benefits of polymeric prosthetics, which are naturally sensitive to light entering the eye and do not require external glasses, cameras, or power sources.”

The research study is based on preclinical models and experimentation will be essential to make the technique a clinical treatment for diseases such as retinitis pigmentosa and age-related macular degeneration.

Provided by Istituto Italiano di Tecnologia