Infrared imaging shines light on biomarkers in cancer cells

New infrared chemical imaging could help fight different forms of cancer by giving doctors a quick and accurate way of detecting biomarkers within cells.

biomarkers in cancer cells
A diagram of wide-field infrared photothermal imaging alongside images of living pancreatic cancer cells it would be used to spot. (Photo courtesy of Yeran Bai/Chinese Academy of Sciences)

In Britain, one-in-eight men will develop prostate cancer during their lifetime and in the US  over 174,000 men are predicted to be diagnosed with the disease this year.

Ji-Xin Cheng, adjunct professor of Purdue University’s Weldon School of Biomedical Engineering and the Department of Chemistry, says a paper in the New England Journal of Medicine found that 1,410 men need to be screened and 48 additional cases of prostate cancer need to be treated to prevent only one death.

“The current examination isn’t precise, so there’s a lot of surgery because doctors can’t tell when there’s a large amount of cancer, whether it’s aggressive or benign,” Cheng said in a statement.

New infrared chemical imaging work involving research by Cheng and Ali Shakouri, the Mary Jo and Robert L. Kirk Director of the Birck Nanotechnology Center in Purdue’s Discovery Park, could change this by allowing better microscopic studies of tissue to detect what anomalies exist and reduce unnecessary surgeries.

“The impact will be big,” Cheng said. “This new method would allow the detection of aggressive breast, prostate and other cancers with biomarker information and at submicron spatial resolution.”

The new technology – detailed in Science Advanceswas developed with collaboration with researchers from Boston University and the Chinese Academy of Sciences.

The paper describes shining an infrared excitation laser and another visible probe laser through a sample and measuring the difference between the hot and cold states. Photothermal detection is used to improve the spatial resolution by one order of magnitude compared to traditional infrared microscopy, providing an opportunity to look for the various biomarkers within the cells.

Cheng and Shakouri used a lock-in camera that was fast enough to handle the million pixels per second in parallel. Shakouri, inventor of the lock-in camera, said the camera detects very small changes in light coming into it.

The research is said to build on work by Cheng and colleagues published three years ago in the same journal. Previous imaging needed eight seconds per image, considered too slow by Cheng because cells and molecules are in constant motion.

Future research will include work to increase the field of view so that the size of the sample that can be examined can be as large as a few millimetres.

Cheng also wants to push the sensitivity to detect very small particles like a single virus or a single bacterium. The latter can allow faster detection of bacterial response to antibiotics.

“Current medical practice is to spend 1-2 days to culture a specimen, then a doctor can tell you if you have an infection or not,” he said. “But if we can measure that at a single bacterium level, that’s a rapid detection. That will be a very important application of this platform.”

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