Electronic Nose Can Diagnose Lung Cancer in Breath Samples Using Gold Nanoparticles
Using an array of sensors made of gold particles measuring just 5-nanometers wide (one nanometer is 1/100,000 the width of a human hair), researchers at the Technion-Israel Institute of Technology have developed an "electronic nose" able to distinguish the breath of lung cancer patients from those without the disease. The research results, published online yesterday on the Website of Nature Nanotechnology, could lead to a rapid and non-invasive way of diagnosing and screening for lung cancer.
“These results show promise as a relatively inexpensive and portable tool that could be used for widespread screening for lung cancer,” said lead researcher Dr. Hossam Haick of the Technion’s Department of Chemical Engineering and the Russell Berrie Nanotechnology Institute. “This is in contrast to existing techniques, which are expensive, slow and require complex instruments.”
According to the World Health Organization, lung cancer is the most common cause of cancer-related death in men and the second most common in women (after breast cancer), and is responsible for 1.3 million deaths worldwide annually. The rising occurrence of the disease and the subsequent effect on health costs could make the proposed technology a possible source of significant savings in both private and public health sectors.
The test population for the study was comprised of 40 patients with primary stage-3 and stage-4 lung cancer, clinically diagnosed by conventional methods. None had received chemotherapy or other cancer treatments prior to breath testing. 56 healthy control subjects were chosen to match the lung cancer study group in age and lifestyle.
Exhaled breath was collected from subjects in a controlled fashion to avoid errors that could arise from not being able to distinguish endogenous compounds (generated by processes in the body, and which provide insight about the body’s functions) and exogenous ones (which can be absorbed via inhalation or through the blood and skin).
Using a process known as gas chromatography/mass spectrometry (GC/MS) studies, thirty-three common volatile organic compounds (VOCs) and nine uncommon VOCs were found in at least 83% of the lung cancer patients and in less than 83% of the healthy subjects. In order to determine the most important breath biomarkers, the researchers also created simulated breath samples based upon GC/MS analyses of lung cancer breath and healthy breath. The perfect overlap between the real and simulated samples, they say, indicates that four biomarkers could be sufficient for diagnosis of the disease.
“This also shows the sensitivity of the gold nanoparticle array is not affected by the presence of water molecules,” said Dr. Haick. “This means there is no need for dehumidification or pre-concentration of the lung cancer biomarkers, and therefore no need to pre-treat the sensors or test subject’s breath in any way.”
Experiments with a wider population of volunteers to thoroughly probe the influence of diet, alcoholism, diabetes, and metabolic and genetic states are underway. The researchers say the technology could also be used to diagnose other conditions and diseases, leading to cost reductions and enhanced possibilities to save lives.
The research was funded by the Marie Curie Excellence Grant of the European Commission’s FP6 program, the Alfred Mann Institute at the Technion, the Israel Cancer Association, and the Technion’s Russell Berrie Nanotechnology Institute.