Cancer Research
Sparkling results in nanoscience
April 8, 2025
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Carbene-coated gold nanoclusters activated by light (seen here as red dots) in tumour cells. (Credit: Courtesy of C2MCI)
Cancer is an increasing public health concern in Canada and worldwide, and scientists across disciplines are searching for ways to improve treatment options, making them safer and more efficient. One of the major challenges in this process is how to target and destroy tumours without damaging healthy cells. At Queen’s (C2MCI), a group of chemists and biophysicists has been working on an innovative approach to cancer therapy using light and very small clusters of gold atoms – and they have started publishing some promising results.
Gold nanoclusters are usually made of less than 100 gold atoms and measure less than two nanometres in diameter (for comparison, a regular sheet of paper is about 100,000 nanometres thick). Over the past few decades, there’s been some excitement about gold nanoclusters in the scientific community because of their potential for both diagnostic and therapeutic applications.
In photodynamic cancer therapies, a photosensitive drug is administered to patients and gets into the cells. Then, when activated by light, the drug destroys the targeted tissue. But one of the challenges in developing these types of therapies is making sure that the treatment destroys cancerous cells, while leaving the healthy ones intact. An ideal drug would enter the organism, get to the targeted cells, and leave without causing damages to the body. Gold nanoclusters are proving to be promising candidates for all that.
The image shows the structure of a carbene-coated gold nanocluster. (Credit: Courtesy of C2MCI)
In two recent papers published in the Journal of the American Chemical Society, the C2MCI team, led by Scientific Director Cathleen Crudden (Chemistry), reports the use of novel, highly stable gold nanoclusters, protected on their surfaces by organic molecules called carbenes.
The Queen's team was able to prepare nanoclusters with such precision that they know exactly how many gold atoms and how many carbenes are on the cluster, and how they are positioned. The clusters were designed to be water soluble – an important characteristic for biomedical applications – and to be filtered by the kidneys and eliminated in urine.
Next, C2MCI put these high-precision materials to the test. Gang Zheng, researcher at the University Health Network and C2MCI team member, showed that the carbene-coated gold nanoclusters were stable in vivo or within the body. Queen’s professor Kevin Stamplecoskie (Chemistry) and team then demonstrated that the clusters are highly luminescent, which facilitates their use in killing cancer cells. Finally, the team showed that the gold nanoclusters are readily taken up by cancerous cells and kill them when irradiated with light.
“These studies are the first key steps in our work to develop novel cancer treatments. While more studies are still necessary, our team is excited about the prospect of improving how we treat cancer with this made-in-Canada invention.”
– Dr. Crudden, Canada Research Chair in Metal Organic Chemistry.
The transformative idea of using thin organic coatings to protect metals is at the core of the C2MCI, created in 2022 with $24 million in support from Canada’s New Frontiers in Research Fund. Dr. Crudden’s discovery of how carbenes can bind to metal surfaces has been referred to by experts as “game-changing,” as it challenged 40 years of understanding how to bind organic species to metal surfaces.
With a team of collaborators across fields including chemistry, physics, engineering and medicine, Dr. Crudden’s groundbreaking discovery is poised to fuel innovation on the nano, micro, and macro scales, with potential applications that range from health care to semiconductor manufacturing and civil engineering. Recently, the C2MCI has started an international research network with partners from Japan and Africa and kicked off four pilot projects to investigate using carbene-coating for improved tuberculosis and cancer therapeutics, modified electrochemical energy conversion and storage, and corrosion protection of renewable energy infrastructure in extreme environments.
“Our interdisciplinary approach to key problems is positioning the institute to make truly meaningful contributions to Canadian society,” says Dr. Crudden. “In addition to providing new potential treatments for those afflicted with cancer and infectious diseases, the institute is making critical inroads improving corrosion protection and designing new microchip manufacturing processes. It's a true pleasure to be able to tackle such important challenges with the phenomenal collaborators, students and postdocs that are part of the C2MCI.”
To read the full papers, visit the Journal of the American Chemical Society ( and ).
