PORTLAND, Ore. Anecdotal evidence that dogs can detect cancer by smell inspired researchers to combine clever chemistry with optical detectors to craft an electronic nose that they claim can not only screen for any kind of cancer, but also determine whether it is aggressive.
A University of Massachusetts chemist and veterinarian collaborated with a Georgia Tech biochemist and materials specialist to craft the laboratory detection system, which they hope to develop into a universal blood test for cancer.
"Dogs may be able to detect cancer, but they can't tell you what kind or how dangerous it is," said University of Massachusetts chemist Vincent Rotello, who worked with fellow professor Joseph Jerry, a veterinarian who specializes in cancer detection.
To automate the alleged canine ability and imbue it with the desired pinpoint accuracy, Rotello and Jerry worked with Georgia Tech professor Uwe Bunz to craft gold nanoparticle-based materials. Like the red, green and blue pixels that mix to represent any color, the different kinds of nanoparticles can mix to cover the whole spectrum of cancer cells, the researchers found. The "RGB-like" fluorescent nanoparticles are mixed with blood or tissue samples, where they bind to suspicious cells and, depending on the combination of particles that light up, indicate whether the cells are metastatic (capable of spreading beyond the initial tumor site).
"Today there are blood tests for specific cancerous antigens, such as those indicative of prostate cancer, but that test does not differentiate between cancer that is aggressive and should be removed [and tumors that are] nonaggressive and better off left alone," said Rotello. "Ours is the first test that can detect any kind of cancer and how dangerous it is."
Next the researchers want to move from animal testing (currently conducted on mice) toward a blood test for humans. "In your bloodstream, you have all sorts of different cells that are sloughed off various organs [and that] can be separated and analyzed," said Rotello. "This is how we could user our 'nose' to do a simple blood test that detects any type of cancer."
The polymer coating supplied to Rotello and Jerry by Bunz is called para-phenyleneethynylene. PPE acquires the ability to glow when displaced from the gold surface of a nanoparticle as a cell attaches itself, allowing the type of cell to be determined by the light patterns generated. The particles are induced to fluorescence with a laser.