Gold nanoparticles used in early detection of lung cancer
By Jeff Salton
September 2, 2009
Gold nanoparticles are being used by researchers in Israel in a new type of breath test to detect lung cancer in patients. Breath particulate analysis isn’t new but the scientists say this is the first time a technique has been used without the need to pre-treat the exhaled breath, delivering a quicker and less expensive diagnosis. Early detection can result in faster treatment and hopefully save lives. Around 25 percent of all cancer-related deaths are lung cancer sufferers, with estimates put at around 1.3 million people dying from the disease each year.
Haick explains that when a patient breathes into the device, particulates in the breath accumulate on the carbon layer, causing the sensor to swell, pushing the gold nanoparticles apart, thus altering the resistance of the film. Each type of particulate has a unique effect on the resistance, which can be measured by having a current flow through the sensor.
"The user gets a figure on the device's display panel that indicates whether the person is healthy or has cancer," says Haick.
No prolonged waiting
The new testing device can provide an almost instant diagnosis of a patient's health, the team says, by utilizing an established, non-invasive method that links ‘volatile organic compounds’ (VOCs) with specific forms of lung cancer.
In present day testing, the drawback of this method is that it requires collecting samples and analyzing them using techniques such as mass spectrometry and infrared spectroscopy, which takes time and forces patients to wait for results. It’s also more costly than the new method.
In order to speed up the diagnosis process, researchers inserted the new sensor into a breath-test device and carried out a series of tests for calibration purposes. By recruiting 96 volunteers – 40 lung cancer patients and 56 controls – the team built up a catalog of VOCs based on the electrical signals that were present in the breath of lung cancer sufferers, but not in the breath of controls.
Haick and his team are currently testing their new device on a wider range of volunteers in order to study the impact of factors like diet, alcohol and genetics. And, in a major break from the convention in medical innovation, the researchers claim they might be able to by-pass full clinical trials and take this new technology to a stage where it is hospital-ready. They believe they could prove the device's accuracy using a series of ‘artificial mixtures’ of particulates that could simulate cancerous and healthy breath.
However, not everyone is convinced skipping the trials is a good idea. Tony Cass, for one, a biomedical engineer at Imperial College, London, has his reservations.
"It has the potential, but will need a lot more clinical validation before it becomes accepted," he says. Cass warns about the danger of oversimplifying real-life cancer diagnoses. "The use of 'synthetic' breath is a good way to test some aspects of the device, but the nature of the approach using sensors, arrays and chemometrics requires evaluation in complex (i.e. real patient) samples," he adds.
Haick has reported that this new device has also shown positive results in diagnosing other diseases including renal failure.
Via Physics World