Silver the key to potential new treatment for cystic fibrosis patients

Research at Victoria University of Wellington could lead to a new antimicrobial to help treat a pathogen currently deadly to cystic fibrosis patients.

Jennifer, wearing a lab coat, stands next to a microscope and looks directly at the camera. There is blurred lab equipment in the background.
Jennifer Soundy

The research, completed by student Jennifer Soundy, who graduates with a PhD in Biotechnology from the University this week, and her supervisor Dr Darren Day from the School of Biological Sciences, studied potential new treatments for Pseudomonas aeruginosa, bacteria that form biofilms in the lungs of cystic fibrosis patients.

“These bacteria are a major cause of death in patients who have cystic fibrosis,” Jennifer says. “They are very difficult to eradicate because they are resistant to many antibiotics as the biofilm layers protect them from most treatments.”

Jennifer’s PhD research began by looking at DNA aptamers and how they could be used to kill pathogens. Aptamers are small sections of DNA that can be custom-coded to target certain areas.

“Originally we hoped to bind our DNA aptamers to the Pseudomonas aeruginosa and kill it, but unfortunately that wasn’t successful,” Jennifer says. “We decided to see if we could bind an antimicrobial to the DNA aptamers instead and then use the aptamers to deliver the antimicrobial straight to the pathogen.”

Jennifer decided to use silver nanoclusters as the antimicrobial. Silver is a well-known antimicrobial that has been used for thousands of years, and because of the way it targets pathogens by attacking multiple cell processes, most pathogens haven’t developed a resistance to it. But she says the problem with silver is that it is toxic in large doses.

“We hoped by binding silver straight to the aptamer and targeting it directly at the pathogen, we could kill the pathogen without harming the host,” Jennifer says. “Excitingly, we were successful at killing the pathogen—it died within ten minutes—and because we could target the pathogen directly we could use very small doses of silver that shouldn’t be harmful to the human body.”

This discovery has many applications, Jennifer says. As well as using silver to treat pathogens directly, the silver could also be combined with other treatments to make those treatments more effective.

“Silver makes pathogens more vulnerable to other treatments, so you could mix a small amount of silver and a small amount of antibiotics together to make a more effective treatment,” Jennifer says. “This could even make pathogens vulnerable to antibiotics that currently have no effect on them. We were able to combine our silver treatment with tobramycin, which is an aerosol treatment currently used to treat Pseudomonas aeruginosa lung infections in cystic fibrosis patients, and initial tests suggest that this combination would be very effective in treating the Pseudomonas aeruginosa.”

Researchers at Victoria University of Wellington will continue work on this project.

“With further research we can improve the effectiveness of the aptamers and work on targeting different pathogens,” says Jennifer’s supervisor Dr Darren Day.

After graduation, Jennifer will begin work at Auramer Bio. Auramer Bio is a biotechnology company that specialises in custom aptamer development that was originally founded through the support of Viclink, Victoria University of Wellington’s commercialisation arm.

Viclink's Senior Commercialisation Manager, Jeremy Jones, says that this technology is another example of the world-leading innovations Victoria University of Wellington researchers are working on.

"Viclink is helping the team accelerate this solution to market and have genuine impacts on patient outcomes," explains Jeremy. "I'm also delighted to see a Viclink spin out company providing a pathway for scientists starting their postgraduate career."