A non-invasive method has been used to locate specific tumors, including small ovarian tumors, in mice. The procedure uses nanotube-based probes to pinpoint tumors with sub-millimeter accuracy. Findings were published in the American Chemical Society journal ACS Applied Materials & Interfaces.
Researchers at Rice University and the University of Texas MD Anderson Cancer Center in Houston, Texas, combined efforts to develop the technique. First, biomarkers linked with carbon nanotubes that can be triggered to emit shortwave infrared light are administered intravenously. They quickly accumulate at the tumor site, and an optical scanner is used to detect the cancer cells using nanotube-based probes.
“The use of affinity probes to locate biological targets is an attractive strategy for noninvasive tumor detection,” explained the authors, led by Rice graduate student Ching-Wei Lin.
In the study, gel-bound carbon nanotubes were surgically implanted into the ovaries of mice to mimic accumulations expected for nanotubes linked with antibodies that recognize tumor cells. The mice were then scanned with a custom optical device that uses spectral triangulation—a method that shows the three-dimensional position of the carbon nanotubes in tissues.
Different types of tissue absorb emissions from the nanotubes differently, so the scanner takes measurements from many locations to triangulate the tumor’s exact location. CT and MRI confirmed the results.
The investigators speculate that this method could find tumors with as few as 100 ovarian cancer cells in humans, which would make it a valuable tool for early detection.
“These results are a step toward the future use of probes with targeting agents such as antibodies linked to nanotube tags for the noninvasive detection and imaging of tumors in preclinical research on small animals,” the authors concluded. “Translation to the clinic could aid in early detection of ovarian cancer and identification of metastases for resection during primary surgery.”
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