A More Sensitive Cancer Breathalyzer

Lung cancer is a brutal disease, often not caught until it's too late for treatment to do much good. Now researchers are building an electronic nose that could help physicians detect the disease during its initial stages. Using gold nanoparticles, scientists at the Israel Institute of Technology in Haifa have created sensors with an unprecedented sensitivity for sniffing out compounds present in the breath of lung-cancer patients.

Breath check: A new device, based on gold-nanoparticle sensors, can detect a mix of volatile organic compounds on the breath that are characteristic of lung cancer. Credit: Nature Nanotechnology

Other attempts to do this have yielded promising results (see Lung-Cancer Breathalyzer and Cancer Breathalyzer), but those devices require a higher concentration of the telltale biomarker chemicals than the Israeli device. The chemicals, called volatile organic compounds (VOCs), are metabolic products present in the vapors that we breathe out, but they occur in such small amounts that researchers have had to find ways to increase their concentrations before testing. Now,Hossam Haick and his colleagues have built sensors using an array of gold nanoparticles that can detect these VOCs in their natural concentrations and under the humid conditions characteristic of human breath. Their research was recently published online in the journal Nature Nanotechnology.

Other devices used for the same kinds of tests depend on expensive means of VOC detection, such as optical sensors, mass spectrometry, and acoustic sensors. These systems aren't always portable, either. Gold-nanoparticle sensors, however, have the potential to be small and inexpensive--the only problem has been getting the VOCs to stick to the gold. "It was quite a lot of work to get them to stick," says Haick, a 2008 TR35 winner. "We're the first to do so, as far as I know." Because of an impending patent, Haick declined to explain how he achieved the desired stickiness. link...