The eye is such a useful feature that it has evolved many times, often with differing structures and capacities. Now, a team of scientists has modeled cameras on two animal eyes very different from our own and each other. They found one can help surgeons remove cancers, while the other can help explain underwater migratory behavior.
For cancer surgeons, one of the greatest challenges is to not leave any cancerous cells behind when removing tumors. To do that, it is essential to be able to distinguish diseased cells from the healthy ones. Chemicals that preferentially bind to tumors and fluoresce in the near infrared can help with the process, but since this is outside the range of human vision we need machines to collect the light and convert it to something surgeons can see. These are expensive and so large they can't even fit into most operating theaters. They also only work well under low light, hindering surgeons' capacity to see the healthy cells they don't want to cut.
Dr Viktor Gruev of the University of Illinois at Urbana-Champaign turned to nature and realized the morpho butterfly found the solution millions of years ago. The butterfly can see in the near-infrared, but also at visible wavelengths, using nanoscale structures that substitute for the color detecting cones in our own retinas.
In Optica, Gruev describes the creation of a camera using similar nanostructures, which detects the infrared fluorescence and feeds a signal to surgical goggles at a frequency human eyes can see. “The surgeon puts on the goggles that have integrated our bio-inspired camera technology, and it will protect their eyes and at the same time project the fluorescent information whenever they want it,” Gruev said in a statement.
Besides eliminating the size and light limitations of current instruments, Gruev estimates that, once mass produced, the camera and goggles will be available for $200, compared to $20,000 for existing options.
Prototypes have been used successfully for surgery on mice, and to remove breast cancer in humans without taking extra tissue. Gruev also demonstrated his invention's versatility by making a dye used to identify lymph nodes for biopsies to glow in the same infrared frequencies. The technique not only enabled the surgeons to find the lymph nodes more quickly but in two patients, it located nodes the surgeons would otherwise have missed.