Type
Text
Type
Thesis
Advisor
Gersappe, Dilip | Gouma, Pelagia-Irene | Sokolov, Jonathan.
Date
2015-12-01
Keywords
Materials Science | biomarker, breath analysis, chemical sensor, tungsten trioxide
Department
Department of Materials Science and Engineering.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76324
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Our breath is a very complex mixture of chemical compositions. Usually, the majority of our exhaled breath consists of nitrogen, oxygen, carbon dioxides, water and inert gases. The remaining small fraction of breath contains thousands of components in trace amount, including inorganic gas molecules like nitric monoxide and diverse kinds of volatile organic compounds (VOCs). The concentrations of our exhaled gases are at a relatively stable level, though minor fluctuations may occur at different time of the day and they are also linked to the body status. Sometimes, if a specific breath gas of some appears to have an abnormal concentration, then it may be a hint that the person is ill. This breath gas therefore provide information of the healthy status of the body and is so-called biomarker. Breath gases have long been used for diagnosis of disease by ancient Greek physicians centuries ago, the foundation of modern breath analysis, however, was established by Nobel Prize winner Linus Pauling in 1971. Though thousands kinds of gases exist in our exhaled breath, only very limited number of them were confirmed by researchers to have a relatively strong linkage to some diseases and become biomarkers. Among all those biomarkers, nitric oxide, acetone and isoprene are the most studied. NO is believed to be in higher concentration in asthmatic patients breath. Acetone concentration is in elevated level in the breath of patients with diabetes. Isoprene is found to be related to cholesterol synthesis in our body. Many techniques have been investigated to detect the existence of biomarkers. Spectroscopy-based techniques are highly accurate in detection of those biomarkers. The tradeoffs are that these devices are very expensive and bulky. In recent years, researchers have been developing chemical sensors mounted on breathalyzers to provide a real-time, non-invasive way for monitoring the concentration levels of breath. Compared to those spectroscopy-based devices, breathalyzers are low in cost, portable, painless and fast in response. In this work, the chemical sensors for NO, acetone and isoprene detection are introduced. The chemical sensors can be divided into several groups based on the output signal. The most common group, chemiresistive sensors, is introduced in detail. In the experiment section, sensor is prepared with γ+ε-WO3 as sensing material and its sensing properties to analyte gases like acetone, isoprene have been tested at different working temperatures. The results showed that the sensor was sensitive to acetone to some extent. However, it also exhibited selectivity to NO due to a coexistence of γ-WO3 and ε-WO3. Therefore, in order to improve the performance of this sensor, elimination of γ-WO3 will be a possible way. | Our breath is a very complex mixture of chemical compositions. Usually, the majority of our exhaled breath consists of nitrogen, oxygen, carbon dioxides, water and inert gases. The remaining small fraction of breath contains thousands of components in trace amount, including inorganic gas molecules like nitric monoxide and diverse kinds of volatile organic compounds (VOCs). The concentrations of our exhaled gases are at a relatively stable level, though minor fluctuations may occur at different time of the day and they are also linked to the body status. Sometimes, if a specific breath gas of some appears to have an abnormal concentration, then it may be a hint that the person is ill. This breath gas therefore provide information of the healthy status of the body and is so-called biomarker. Breath gases have long been used for diagnosis of disease by ancient Greek physicians centuries ago, the foundation of modern breath analysis, however, was established by Nobel Prize winner Linus Pauling in 1971. Though thousands kinds of gases exist in our exhaled breath, only very limited number of them were confirmed by researchers to have a relatively strong linkage to some diseases and become biomarkers. Among all those biomarkers, nitric oxide, acetone and isoprene are the most studied. NO is believed to be in higher concentration in asthmatic patients breath. Acetone concentration is in elevated level in the breath of patients with diabetes. Isoprene is found to be related to cholesterol synthesis in our body. Many techniques have been investigated to detect the existence of biomarkers. Spectroscopy-based techniques are highly accurate in detection of those biomarkers. The tradeoffs are that these devices are very expensive and bulky. In recent years, researchers have been developing chemical sensors mounted on breathalyzers to provide a real-time, non-invasive way for monitoring the concentration levels of breath. Compared to those spectroscopy-based devices, breathalyzers are low in cost, portable, painless and fast in response. In this work, the chemical sensors for NO, acetone and isoprene detection are introduced. The chemical sensors can be divided into several groups based on the output signal. The most common group, chemiresistive sensors, is introduced in detail. In the experiment section, sensor is prepared with γ+ε-WO3 as sensing material and its sensing properties to analyte gases like acetone, isoprene have been tested at different working temperatures. The results showed that the sensor was sensitive to acetone to some extent. However, it also exhibited selectivity to NO due to a coexistence of γ-WO3 and ε-WO3. Therefore, in order to improve the performance of this sensor, elimination of γ-WO3 will be a possible way. | 43 pages
Recommended Citation
Li, Yan, "Breath biomarkers detection by chemical sensors" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2248.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2248