How tiny gold particles may help restore vision

Gold might not just be for jewelry anymore – it could also hold the key to restoring vision. Researchers are exploring a surprising new approach to treating blindness caused by retinal disorders.

Their focus? Gold nanoparticles – microscopic particles thousands of times thinner than a human hair.

In a recent study from Brown University, researchers discovered that gold nanoparticles, when injected into the retina and paired with infrared light, could restore visual function in mice.

The work, supported by the National Institutes of Health, points to a future where people with diseases like macular degeneration might regain some level of sight through a non-invasive treatment that doesn’t require surgery or gene editing.

A high-tech vision fix

Millions of people worldwide suffer from retinal diseases like macular degeneration and retinitis pigmentosa. These conditions damage photoreceptors – the rods and cones responsible for turning light into electrical signals in the eye.

When these cells stop working, the rest of the visual chain is disrupted. However, not all parts of the retina are affected. Cells called bipolar and ganglion cells, which sit further along the visual processing pathway, often remain intact.

That’s where the nanoparticles come in. This new approach bypasses the damaged photoreceptors. Instead, it uses a special solution of gold nanoparticles injected directly into the retina.

Using gold to restore vision

When these particles are hit with infrared light, they heat up ever so slightly – just enough to activate the bipolar and ganglion cells. This stimulation mimics how the retina normally responds to light, offering a potential way to restore vision.

“This is a new type of retinal prosthesis that has the potential to restore vision lost to retinal degeneration without requiring any kind of complicated surgery or genetic modification,” said Jiarui Nie, who led the study during her Ph.D. work at Brown University.

“We believe this technique could potentially transform treatment paradigms for retinal degenerative conditions.”

Testing the technique

The researchers first tested their approach using mouse retinas in a lab dish. Later, they moved on to live mice with retinal damage. After injecting the gold nanoparticles, the team used a patterned infrared laser to project shapes onto the retina.

Using a calcium signal to track cell activity, the experts saw that the nanoparticles activated the correct cells – and in patterns that matched the projected laser shapes.

The researchers also checked for safety. They looked at metabolic markers to detect inflammation or toxicity and found no signs of major side effects.

Using special probes, they confirmed that the laser light triggered brain activity in the visual cortex of the mice. That’s an important clue – it shows that the visual information was making its way to the brain, suggesting that vision was being restored at least in part.

Gold nanoparticles meet lasers

Looking ahead, the team imagines a wearable system combining the nanoparticles with laser technology.

A pair of high-tech glasses or goggles would house a small infrared laser and a camera. The camera would gather real-world images, which would be turned into laser pulses aimed at the retina. Those pulses would activate the nanoparticles, helping the brain perceive visual information.

There’s already a somewhat similar system on the market – an FDA-approved device that uses a surgically implanted electrode array. But the nanoparticle technique has some clear advantages.

For one, it’s far easier to administer. “An intravitreal injection is one of the simplest procedures in ophthalmology,” explained Nie. That’s much less complicated than implanting an electronic device inside the eye.

Improving vision with gold

Beyond the simpler delivery, the new method could offer better visual coverage. The earlier electrode-based systems only had around 60 pixels of resolution – hardly enough for detailed vision.

But the nanoparticle solution spreads across the entire retina. That means it could potentially help someone see across their full field of view. And because it uses near-infrared light rather than visible light, it might not interfere with whatever natural vision a person still has.

“We showed that the nanoparticles can stay in the retina for months with no major toxicity,” Nie said. “And we showed that they can successfully stimulate the visual system. That’s very encouraging for future applications.”

While more testing is needed before this can be used in human patients, the research shows real promise. If future studies continue to show positive results, this simple and non-invasive approach could become an important tool for restoring sight to people who’ve lost it.

The full study was published in the journal ACS Nano.

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