Health Status Monitoring by Discrimination of Exhaled Breath with an Electronic Nose Thara Seesaard Materials Science and Engineering Programme and Center of Intelligent Materials and Systems (CIMS) Faculty of Science, Mahidol University Bangkok, Thailand Teerakiat Kerdcharoen * and Sumana Kladsomboon Department of Physics, Faculty of Science Mahidol University, Bangkok, Thailand teerakiat@yahoo.com Panida Lorwongtragool Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi Nonthaburi, Thailand Taya Kitiyakara * Division of Gastroenterology and Hepatology Faculty of Medicine Ramathibodi Hospital Mahidol University, Bangkok, Thailand tayakiti@googlemail.com Abstract—In an aging society, people unprecedentedly spend more attention to routine assessment of their health status. Besides self-check and doctor’s examination, there are also biomedical devices capable of monitoring and indicating the status of human health. In this paper, we proposed an electronic nose system that has been developed to have the ability to detect odor from human breath in order to indicate the health status of its owner. Metal-porphyrins (MPs)/SWNT-COOH and polymer/SWNT-COOH nanocomposites sensors were used as the array of chemical gas sensors inside the electronic nose system. These sensing materials are sensitive to odor molecules presented in the exhaled breath. The constructed device consumes low power and can be operated at room temperature. A preliminary experiment was conducted on the sample group consisting of cancer patients and healthy volunteers to distinguish their health status indicating diseases. It was found that the e-nose can detect exhaled breath odors and discriminate the pattern of breath odor of each person. This will be useful in discriminating one’s breath odor and identifying his health status. This device could help reduce the risks of getting infected from any disease beforehand. Index Terms—Cancer detection, electronic nose, exhaled breath, gas sensors, PCA, volatile organic compounds (VOCs). I. INTRODUCTION Nowadays, people’s lifestyles have changed in various aspects; labors have changed to be the brain workers. Living a busy life leads to lacking of exercise, not having healthy food, paying no attention to one’s own health. These were the causes of many diseases such as cancer, coronary heart disease, stroke and hypertension. In particular, cancer is a primarily cause of death especially liver cancer which was ranked the fifth in the world. Furthermore, it was considered the number one cause of death in Thai men [1]. Liver cancer, hepatocellular carcinoma (HCC), has been one of the most vital diseases. When the symptom appears, it means that the patient is in a dangerous stage. In general, patients will die of the liver cancer within a few months after it was detected. A higher level of α-fetoprotein (AFP) has been used to diagnose liver cancer and screen of the level of AFP, but it is not efficient enough to treat cancer. The patient has to undergo radiological imaging such as CT scan, Angiography, Laparoscopy, blood examination and ultra-sounded in every 6 months [2]. These special treatments are costly and because they are usually used in the critical stage, not all of them end up successfully. Many Thai people do not have the opportunity to access to these kinds of treatment. New screening methods that are more convenient and cheaper can help reduce a number of people dying of cancer. Therefore, researchers have been interested to develop the diagnosis method based on chemical vapors [3-4]. The method is based on the assumption that the cancer cells release some marker substances. This enables a doctor to identify some specific odor of each type of cancer. The findings suggest that different physical conditions lead to variety of chemical substances in exhaled breath, which is specific to each person’s physical conditions. Patients with cirrhosis have aliphatic acid in their breath, while patients with kidney failure have dimethylamine and trimethylamine in their breath. Similarly, patients with lung cancer have substances such as alkanes, aldehydes and derivatives of benzene in their breath. [5]. The exhaled breath odor was excreted from respiratory of human body in the form of volatile organic compounds, (VOCs) [6-7] which can be detected and analyzed by odor detector such as the solid phase micro-extraction (SPME) and gas chromatography with mass spectroscopy or GC/MS. Most previous studies focus on lung cancer and breast cancer [8-9]. Recently, the study on the exhaled breath test of malignant mesothelioma (MM) patient using an electronic nose has been published [10]. This kind of tumor is rarely found in the patients. Electronic nose was not only used to test the breath of the patients with lung cancer and the diseases caused by malfunction in respiratory system such as chronic obstructive pulmonary disease and asthma [11-12], but it was also used to analyze sputum sample of the patients with tuberculosis [13]. Unfortunately, there was only one research on chemical substances in the breath of patients with liver cancer (HCC) The 2012 Biomedical Engineering International Conference (BMEiCON-2012) 978-1-4673-4892-8/12/$31.00 ©2012 IEEE