Gargle with gold to find oral cancer
Imagine buying a kit at your local pharmacy to test for oral cancer.
That may become a reality, thanks to Dror Fixler and his team at the Advanced Light Microscopy Laboratory at Israel’s Bar-Ilan University. They have invented a mouthwash embedded with gold nanoparticles — a noninvasive optical system that detects cancer of the head, neck, tongue or throat.
This technology can diagnose cancers that currently must be confirmed by surgical biopsy. The solution was successfully tested in animal models, showing 97 percent specificity and 87.5 percent sensitivity.
Now the gold gargle is in human trials supervised by two top physicians at Chaim Sheba Medical Center at Tel Hashomer: Michael Wolff, head of the department of otolaryngology, head and neck surgery; and Avraham Hirshberg, a researcher in the department of oral pathology and oral medicine. In addition, the university’s technology transfer company is in early talks with potential commercial partners.
The three-year research behind this breakthrough constituted the doctoral thesis of Fixler’s student Rinat Ankri. “Gold nanoparticles were already used for finding cancer cells,” she said. “Our job was figuring out how to use them in our optical setup for detection.”
Fixler, a renowned electro-optics expert, had the notion of combining two existing technologies to make this idea work. Nobody ever thought about such a combination before, he said, perhaps because they are from totally different disciplines — one from pure physics and the other from biomolecular imaging.
“I am always thinking how I can use my knowledge and budget to do what smarter and richer people haven’t accomplished,” he joked.
From the discipline of physics he focused on diffusion reflection, until now a theoretical approach to learning about the properties of an object by shining a light on it and measuring the intensity of the light versus the distance from its source. He mixed that idea with quantum optics, where nano-sized particles are coated with antibodies to react visually with a specific target antigen — for example, cancer cells — that cannot otherwise be detected.
“Some companies already have commercial products based on this principle, but they need a very high concentration of particles in order to see anything,” Fixler said.
If one technology was only theoretical and the other impractical, putting them together yielded an innovation that works. Fixler and Ankri coated gold nanoparticles with an antibody and injected them, but instead of looking for where they linked up with antigens on the target cells, they used diffusion reflection to measure how the nanoparticles influence the intensity versus the distance of the light.
“The nanoparticles change the optical properties of the tissue in a way that is unique to this tissue. Using a very low amount of gold, I can show via a new imaging technique that the particles are there,” explained Fixler, who has co-written more than 10 papers about this breakthrough. The most recent was published in the Journal of Dental Research.
After learning that injecting gold nanoparticles into the body can cause unwanted side effects, Fixler and Ankri decided to concentrate their efforts on detecting surface cancers. The solution can be brushed onto the skin or used as a mouthwash.
Fixler says it is safe and inexpensive, especially compared with invasive cancer-detection methods. Gold nanoparticles can be made in the lab or purchased off the shelf. He estimates that the kit might cost in the range of $200. “We hope at the end of 2015 we will have two operating systems in two clinics for regular use,” Fixler said.
“We are now concentrating on making a portable device,” Ankri said. “We are also trying to adjust the system to detect other abnormalities, such as plaques signifying arteriosclerosis. Here you’d have to inject the gold nanoparticles into specific blood vessels.”
The Bar-Ilan Research & Development (BIRAD) owns the patents and is working toward commercializing the cancer-detection kit.
“We are in discussions with a couple of potential commercial partners,” BIRAD director Orli Tori said. Although she cannot name them, she added, “We usually try to begin with Israeli partners, as one of our mission statements is to encourage economic development in Israel. In this case, we are looking to build up a new company.”