Injectable nanoparticles restored light sensitivity in blind retinas during preclinical trials, with results published in Nature Biomedical Engineering and supported by experiments on mice and pig tissue, according to Aarhus University-led research.
Researchers at Aarhus University have developed injectable nanoparticles that enable blind retinas to respond to light, marking a breakthrough in retinal prosthesis research. The hollow graphitic carbon nitride particles, approximately 300 nanometers in diameter, bypass damaged photoreceptors by directly stimulating surviving retinal nerve cells, as demonstrated in experiments on mice and isolated pig retinal tissue.
How the Nanoparticles Work
The nanoparticles, inspired by plant chloroplasts, capture visible light and generate local photoelectrochemical effects that trigger calcium transients in nearby cells. This process activates retinal ganglion cells, which transmit visual signals to the brain. When we started, our fundamental question was whether we could create a material that could act as a wireless interface between light and living cells,
said Dr. Menglin Chen, lead researcher at Aarhus University. We can now see that the particles are able to activate nerve cells in blind retinas.
In mice with advanced retinitis pigmentosa, the nanoparticles induced detectable light responses in the visual cortex and prompted behavioral changes. Similar results were observed in pig retinal tissue, where LED light stimulated ganglion cells in the presence of the particles. What is particularly interesting is that we are trying to make use of the nerve cells that still function in the retina,
Chen added. Instead of genetically modifying these cells, we use the nanoparticles to create a new connection between light and the nerve cells.
Comparing to Existing Treatments
Unlike gene therapy, optogenetics, or electronic implants, this approach avoids genetic modification and invasive surgery. Once the photoreceptors are lost, the options for restoring light sensitivity are still very limited,
said retina specialist Henri Leinonen, a co-author of the study. That is why it is worth testing strategies that work independently of the cause of the disease.
The method’s mutation-agnostic nature sets it apart, as it does not rely on specific genetic targets or viral vectors.
The particles’ wireless mechanism contrasts with traditional retinal implants, which require surgical placement of hardware. We are trying to make a blind retina respond to light again,
Chen said. The study, published in Nature Biomedical Engineering, details how the nanoparticles induce calcium-transient release in multiple cells and propagate signals in cardiac and retinal tissues.
Next Steps and Challenges
While the technology does not restore full vision, it represents a critical step toward a new class of retinal prostheses. The research team, supported by a 2025 Novo Nordisk Pioneer grant, now focuses on optimizing nanoparticle delivery, assessing long-term safety, and refining light-evoked responses. The next steps are substantial,
said Chen. We need to refine delivery, assess how long the nanoparticles remain functional in the eye, study their long-term safety, and determine whether the light-evoked responses can be strengthened.
Broader Implications for Medical Science
The research highlights the potential of biomimetic materials in regenerative medicine. By mimicking natural processes, the nanoparticles demonstrate a novel way to interface with biological systems without invasive interventions. What we show here is a light-evoked response in a degenerated retina, which is an early step rather than a finished prosthesis,
said Leinonen. The study’s findings could influence future therapies for neurodegenerative diseases beyond the eye, leveraging light-sensitive materials to modulate cellular activity.
The work builds on a 2019 Carlsberg OptoMed grant and a 2024 patent filing, reflecting years of development. With support from institutions like the University of Chicago and Aarhus University Hospital, the project underscores the interdisciplinary collaboration needed to advance medical innovation. As preclinical trials progress, the focus remains on translating this proof-of-concept into a viable treatment for patients with vision loss.