Camera mimics butterfly eyes to help surgeons see cancer cells

Researchers have created a camera that mimics the visual system of a butterfly to help surgeons remove cancerous cells without damaging healthy tissue, reducing the likelihood of the cancer spreading.

The camera provides both a traditional color image and a near-infrared image that allows fluorescently labeled cancerous cells to be visible, even under bright surgical lighting.  

"We looked to nature's visual systems for inspiration," said Viktor Gruev, research team leader and associate professor of electrical and computer engineering at the University of Illinois at Urbana-Champaign, in a statement. "The morpho butterfly, whose eyes contain nanostructures that sense multispectral information, can acquire both near-infrared and color information simultaneously."

In a paper published Thursday in the journal Optica, the researchers explained how their camera can detect tumors in animals and can help assess the stage of breast cancer in humans. The camera weighs less than an ounce and can be manufactured for about $20, they say. 

The camera's ability to detect fluorescence markers under surgical lighting sets it apart from many of today's FDA-approved near-infrared cameras, which aren't sensitive enough to do this, according to the researchers. Room lights typically need to be dimmed to see the fluorescence. 

Also, the fluorescence image from most infrared imagers doesn't always line up with the tissue it's looking at. That's because the instruments use more than one optical element to separate visible and infrared wavelengths, so each can be sent to different detectors. A slight temperature change in the room can change the optics and cause image misalignment, which could lead a surgeon to miss cancerous tissue and accidentally remove healthy tissue. 

Missael Garcia, a post-doctoral researcher at the University of Illinois at Urbana-Champaign and lead author of the paper, said they realized these problems could be mitigated by using nanostructures that resemble those of the morpho butterfly.

"Their compound eyes contain photoreceptors located next to each other such that each photoreceptor senses different wavelengths of light in a way that is intrinsically coregistered," Garcia said in the statement.

The researchers' camera integrates the detector and imaging optics into one sensor, keeping the device small and inexpensive. 

The imager could be useful for removing a variety of cancers, including melanomas, prostate cancer and head and neck cancers, according to the researchers. Thanks to its compact size, it could also be put into an endoscope to look for cancer in a colonoscopy. 

The team is creating a start-up to commercialize the device. They're also working with the FDA to design a clinical trial that would compare clinical decisions made with their imager to those made with FDA-approved devices.

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