Tag: gold

Categories : New Compounds and Treatments OphthalmologyTags : Leave a comment

Goldeneye: Research on Restoring Eyesight with Gold Nanoparticles

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Retina showing reticular pseudodrusen. Although they can infrequently appear in individuals with no other apparent pathology, their highest rates of occurrence are in association with age-related macular degeneration (AMD), for which they hold clinical significance by being highly correlated with end-stage disease sub-types, choroidal neovascularisation and geographic atrophy. Credit: National Eye Institute

A new study by Brown University researchers suggests that gold nanoparticles might one day be used to help restore vision in people with macular degeneration and other retinal disorders. 

In a study published in the journal ACS Nano and supported by the National Institutes of Health, the research team showed that nanoparticles injected into the retina can successfully stimulate the visual system and restore vision in mice with retinal disorders. The findings suggest that a new type of visual prosthesis system in which nanoparticles, used in combination with a small laser device worn in a pair of glasses or goggles, might one day help people with retinal disorders to see again. 

“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, research leader and now a postdoctoral researcher. “We believe this technique could potentially transform treatment paradigms for retinal degenerative conditions.” 

Nie performed the work while working in the lab of Jonghwan Lee, an associate professor in Brown’s School of Engineering and a faculty affiliate at Brown’s Carney Institute for Brain Science, who oversaw the work and served as the study’s senior author. 

Retinal disorders like macular degeneration and retinitis pigmentosa affect millions of people in the U.S. and around the world. These conditions damage light-sensitive cells in the retina called photoreceptors — the “rods” and “cones” that convert light into tiny electric pulses. Those pulses stimulate other types of cells further up the visual chain called bipolar and ganglion cells, which process the photoreceptor signals and send them along to the brain. 

This new approach uses nanoparticles injected directly into the retina to bypass damaged photoreceptors. When infrared light is focused on the nanoparticles, they generate a tiny amount of heat that activates bipolar and ganglion cells in much the same way that photoreceptor pulses do. Because disorders like macular degeneration affect mostly photoreceptors while leaving bipolar and ganglion cells intact, the strategy has the potential to restore lost vision. 

In this new study, the research team tested the nanoparticle approach in mouse retinas and in living mice with retinal disorders. After injecting a liquid nanoparticle solution, the researchers used patterned near-infrared laser light to project shapes onto the retinas. Using a calcium signal to detect cellular activity, the team confirmed that the nanoparticles were exciting bipolar and ganglion cells in patterns matched the shapes projected by the laser.

The experiments showed that neither the nanoparticle solution nor the laser stimulation caused detectable adverse side effects, as indicated by metabolic markers for inflammation and toxicity. Using probes, the researchers confirmed that laser stimulation of the nanoparticles caused increased activity in the visual cortices of the mice — an indication that previously absent visual signals were being transmitted and processed by the brain. That, the researchers say, is a sign that vision had been at least partially restored, a good sign for potentially translating a similar technology to humans. 

For human use, the researchers envision a system that combines the nanoparticles with a laser system mounted in a pair of glasses or goggles. Cameras in the goggles would gather image data from the outside world and use it to drive the patterning of an infrared laser. The laser pulses would then stimulate the nanoparticles in people’s retinas, enabling them to see. 

The approach is similar to one that was approved by the Food and Drug Administration for human use a few years ago. The older approach combined a camera system with a small electrode array that was surgically implanted in the eye. The nanoparticle approach has several key advantages, according to Nie.

For starters, it’s far less invasive. As opposed to surgery, “an intravitreal injection is one of the simplest procedures in ophthalmology,” Nie said. 

There are functional advantages as well. The resolution of the previous approach was limited by the size of the electrode array — about 60 square pixels. Because the nanoparticle solution covers the whole retina, the new approach could potentially cover someone’s full field of vision. And because the nanoparticles respond to near-infrared light as opposed to visual light, the system doesn’t necessarily interfere with any residual vision a person may retain.   

More work needs to be done before the approach can be tried in a clinical setting, Nie said, but this early research suggests that it’s possible.

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

Source: Brown University

Categories : Cancer New Compounds and TreatmentsTags :

Gold Trumps Platinum for Chemotherapy Compounds

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Left: Normal cervical cancer cells with well-formed nuclei in blue and elongated actin filaments – which play an essential role in cell survival and division – in green. Right: Destabilised cervical cancer cells after gold compound treatment show structural integrity compromised while the nuclei in blue are breaking apart, indicating cell death. Credit: RMIT University

Gold-based drugs can slow tumour growth in animals by 82% and target cancers more selectively than standard chemotherapy drugs, according to new research out of RMIT University. The study published in the European Journal of Medicinal Chemistry reveals a new gold-based compound that’s 27 times more potent against cervical cancer cells in the lab than standard chemotherapy drug cisplatin. 

It was also 3.5 times more effective against prostate cancer and 7.5 times more effective against fibrosarcoma cells in the lab. In mice studies, the gold compound reduced cervical cancer tumour growth by 82%, compared to cisplatin’s 29%. 

Project lead at RMIT, Distinguished Professor Suresh Bhargava AM, said it marked a promising step towards alternatives to platinum-based cancer drugs.  

“These newly synthesised compounds demonstrate remarkable anticancer potential, outperforming current treatments in a number of significant aspects including their selectivity in targeting cancer cells,” said Bhargava, Director of RMIT’s Centre for Advanced Materials and Industrial Chemistry. “While human trials are still a way off, we are really encouraged by these results.” 

The gold-based compound is patented and ready for further development towards potential clinical application.

Gold: the noblest element

Photo by Jingming Pan on Unsplash

Gold is famously known as the noblest of all metals because it has little or no reaction when encountering other substances. However, the gold compound used in this study is a chemically tailored form known as Gold(I), designed to be highly reactive and biologically active.  

This chemically reactive form was then tailored to interact with an enzyme abundant in cancer cells, known as thioredoxin reductase.

By blocking this protein’s activity, the gold compound effectively shuts down cancer cells before they can multiply or develop drug resistance. 

Project co-lead at RMIT, Distinguished Professor Magdalena Plebanski, said along with this ability to block protein activity, the compound also had another weapon in its anti-cancer arsenal. 

In zebrafish studies, it was shown to stop the formation of new blood vessels that tumours need in order to grow. 

This was the first time one of the team’s various gold compounds had shown this effect, known as anti-angiogenesis.  

The drug’s effectiveness at using these two attacks simultaneously was demonstrated against a range of cancer cells. 

This included ovarian cancer cells, which are known to develop resistance to cisplatin treatment in many cases. 

“Drug resistance is a significant challenge in cancer therapy,” said Plebanski, who heads RMIT’s Cancer, Ageing, and Vaccines Laboratory.

“Seeing our gold compound have such strong efficacy against tough-to-treat ovarian cancer cells is an important step toward addressing recurrent cancers and metastases.” 

Gold has been a cornerstone of Indian Ayurvedic treatments for centuries, celebrated for its healing properties. Today, gold-based cancer treatments are gaining global traction, with advancements such as the repurposing of the anti-arthritic drug auranofin, now showing promise in clinical trials for oncology. 

“We know that gold is readily accepted by the human body, and we know it has been used for thousands of years in treating various conditions,” Bhargava said.

“Essentially, gold has been market tested, but not scientifically validated. 

“Our work is helping both provide the evidence base that’s missing, as well as delivering new families of molecules that are tailor-made to amplify the natural healing properties of gold,” he said.

Bhargava said this highly targeted approach minimises the toxic side effects seen with the platinum-based cisplatin, which targets DNA and damages both healthy and cancerous cells.

“Their selectivity in targeting cancer cells, combined with reduced systemic toxicity, points to a future where treatments are more effective and far less harmful,” Bhargava said. 

This specific form of gold was also shown to be more stable than those used in earlier studies, allowing the compound to remain intact while reaching the tumour site. 

Categories : GastrointestinalTags :

Gold Nanoparticles Ease IBD Inflammatory Symptoms

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Gold bars
Photo by Jingming Pan on Unsplash

In a Chinese study published in Fundamental Research, researchers explored a treatment for inflammatory bowel disease (IBD) using ultrasmall gold nanoparticles. Previous studies showed that these nanoclusters effectively eliminate a variety of reactive oxygen species (ROS), elevated levels of which are commonly found in the gastrointestinal tract of IBD patients.

IBD includes ulcerative colitis and Crohn’s disease, both of which tend to be debilitating, lifelong conditions that can prove fatal in severe cases. Currently, there is no cure for IBD. The main clinical treatments are drugs such as aminosalicylic acid preparations and corticosteroids, but they are often accompanied by gastrointestinal problems, anaemia, and various intestinal complications. Finding alternative, more effective options is a priority for researchers.

The team found that administering gold (Au25) nanoclusters orally to mice suffering from colitis eliminated ROS, increased antioxidant enzymes, and inhibited pro-inflammatory cytokines, without any obvious side effects. According to paper author Fei Wang of China’s The Seventh Affiliated Hospital of Sun Yat-Sen University, a reduction in the inflammation in the gastrointestinal tracts of the mice was observed within 24 hours. She added: “And the fact that these nanoclusters can be administered orally, means there is no need for invasive procedures.”

Additionally, the team found that the nanoclusters have a number of benefits when compared with natural enzymes used in traditional IBD treatments, including lower cost, better stability, mass synthesis and easier storage. Wang explained: “The storage of Au25 nanoclusters was not affected by pH, temperature or solution medium, and their good physiological stability and acid resistance meant they were easily able to access the inflamed colon. They also have good biocompatibility and chemical stability and can remove a variety of ROS.”

Wang concluded: “Au25 nanoclusters offer a promising strategy in the research field of nanomedicine therapy for IBD. We believe this study demonstrates their value as a scientific basis and experimental basis for the clinical treatment of IBD.”

Source: EurekAlert!