Joon-Boo Yu

Exhaled Breath Analysis of Lung Cancer Patients Using a Metal Oxide Sensor

Exhaled breath gases include gases generated in the body. When there is disease in the body, exhalation can include gas components from the disease. If we can find these specific elements through analysis of the exhalation gases, this can be an effective way to diagnose the disease. The lung has a close relationship with exhalation. Lung cancer refers to malignant tumors which originate in the lungs. Exhalation from the lung causes direct jets of gas to be ejected through the mouth and nose, so by analyzing these jets it may be possible to diagnose lung cancer. In our study we attempt to diagnose lung cancer from patient`s exhaled gases. Exhalation of lung cancer patients was analyzed using gas chromatography-mass spectroscopy(GC-MS) and the expiratory gas was also measured using a sensor system. The system was designed to use a metal oxide sensor and solid phase micro extraction(SPME) fiber. The GC-MS analysis of the healthy subject`s and cancer patient`s exhalation gases both showed the presence of decane in the breath of patients with lung cancer. In addition, the results from the sensor system showed significant difference between the lung cancer patients and the healthy subjects.

Sensing characteristics of nano-network structure of polypyrrole for volatile organic compounds (VOCs) gases

Nanowires of conducting polypyrrole (PPy) were synthesized by chemical polymerization methode. The 0.18 mol of pyrrole (Py) as monomer, 0.18 mol of dodecyl-benzene sulfonic acid (DBSA) as dopant and 0.26 mol of anhydrous iron(lll) tri chloride (FeCl3) as oxidant were mixed and stirred in 200 ml of distilled water at 0degC. The reaction was carried out for three different times (6 h, 24 h, 40 h) and reaction rate was 200 rpm. The morphology of PPy was evaluated by field emission scanning electron microscopy (FE-SEM). It was found that the morphology of nanowire PPy was affected by reaction time and aggregation rate. When the polymerization time was getting longer, nanowire structure was appeared clearly. The sensitivities of nanowire PPy were investigated with volatile organic compounds (VOCs).

Investigation of Exhaled Breath Samples from Patients with Alzheimer’s Disease Using Gas Chromatography-Mass Spectrometry and an Exhaled Breath Sensor System

Exhaled breath is a body secretion, and the sampling process of this is simple and cost effective. It can be non-invasively collected for diagnostic procedures. Variations in the chemical composition of exhaled breath resulting from gaseous exchange in the extensive capillary network of the body are proposed to be associated with pathophysiological changes. In light of the foreseeable potential of exhaled breath as a diagnostic specimen, we used gas chromatography and mass spectrometry (GC-MS) to study the chemical compounds present in exhaled breath samples from patients with Alzheimer’s disease (AD), Parkinson’s disease (PD), and from healthy individuals as a control group. In addition, we also designed and developed a chemical-based exhaled breath sensor system to examine the distribution pattern in the patient and control groups. The results of our study showed that several chemical compounds, such as 1-phenantherol and ethyl 3-cyano-2,3-bis (2,5,-dimethyl-3-thienyl)-acrylate, had a higher percentage area in the AD group than in the PD and control groups. These results may indicate an association of these chemical components in exhaled breath with the progression of disease. In addition, in-house fabricated exhaled breath sensor systems, containing several types of gas sensors, showed significant differences in terms of the normalized response of the sensitivity characteristics between the patient and control groups. A subsequent clustering analysis was able to distinguish between the AD patients, PD patients, and healthy individuals using principal component analysis, Sammon’s mapping, and a combination of both methods, in particular when using the exhaled breath sensor array system A consisting of eight sensors. With this in mind, the exhaled breath sensor system could provide alternative option for diagnosis and be applied as a useful, effective tool for the screening and diagnosis of AD in the near future.

Chemical Sensors Array Optimization Based on Wilks Lamda Technique

Abstract Optimizing the performance of a composite sensor array is necessary when the number of sensors to choose from is large. In thispaper, we present a chemical sensors array optimization method using Wilks Lamda algorithm applicable a device to detect low con-centration of alcohol from driver’s exhale breath for interlocking engine ignition preventing drink-driving. More than 20 chemical sen-sors fabricated different synthetic stuffs and heater temperatures by collaborators were nominated, 5 sensors were selected for optimalsensors array using the method, and alcohol samples were well discriminated from the interference gases inside the vehicle. It has beenconfirmed by Principal Component Analysis (PCA).Keywords: Sensors array optimization, Wilks lamda technique, Alcohol detection, Drink-driving 1. 서론 우리나라는 2011년 OECD 회원국 중 교통사고 발생 건수가미국, 일본, 독일 다음인 4위(221,711건)를 차지하고 있으며, 이중 음주운전으로 인한 교통사고 발생이 약 12% 차지하고 있으며, 이는 2005~2009년 사이의 점유율과 비슷한 수준으로 여전히 줄어들지 2 않고 있다. 이러한 음주운전과 관련한 교통사고를감소시키고자, EU는 2005년 CENELEC(유럽전기기술표준위원회), 일본은 2013년 MILT(국토교통성)에서알코올 인터락 (interlock)장치에 대한 가이드 라인을 발표 하였다. 알코올 인터락 장치는운전자의 음주 측정을 위한 알코올 센서가 가장 중요한 역할을하며, 그 알코올 센서는 여러 가스들이 혼재되어 있는 차량 내부에 설치 된다. 이러한 환경에서 알코올의 원활한 검지를 위해서는 알코올과 함께 혼재되어 있는 간섭 가스(interference gases)들 모두 검지 및 분류가 가능한 센서 어레이를 구성 하여야 한다. 또한 센서 어레이를 구성하기 위한 센서의 선택은 다양한간섭 요인들을 극복하는 동시에 정확한 목적가스(target gas)의인식이 가능하도록 하여야 한다. 이러한 센서 어레이를 위한 센서 선택 및 구성을 위하여 본 논문에서는 Wilks Lamda방법을이용한 센서 어레이 최적화를 제안한다[1-3]. 덧붙여서 본 연구를 위한 센서 및 센서 데이터들은 공동연구기관인 ㈜센텍과 고려대학교로부터 제공되었으며, 해당 센서들은 Ni, Cr, Pt등의 촉매가 내부에 도포된 튜브형 SnO나노섬유를 전기방사와 Sputtering공정을 결합하여 합성되었다[4].

Gas Sensing Property and Humidity Effect of Polypyrrole and SnO2 Composite Films

Conducting polymer (Polypyrrole) and tin oxide (SnO2) composite films have been fabricated with layer-by-layer technique. SnO2 film was screen-printed on Al2O3 substrate and then it was dip-coated with polypyrrole (PPy) solution. The microstructures of composite films were evaluated by a field emission scanning electron microscope (FE-SEM). It was observed the sensing properties of PPy/SnO2 sensor to various VOCs. Methanol, ethanol, benzene and toluene were analyzed. The target vapors were vaporized using their vapor presents and their concentrations were precisely controlled using mass flow controller (MFC) and temperature controller. The reproducibility of sensing properties was evaluated and the humidity effect of PPy/SnO2 was checked.

The Characteristics of ZnO/SnO 2 Sensing Materials by Ultrasonic and Hydrothermal Treatments to Volatile Organic Compounds

The important factors in sensors are sensitivity, selectivity, and response time. Oxide semiconductors are high sensitivity, fast response and the advantage of miniaturization. Zn-doped materials have been synthesized in order to improve the selectivity of the sensor. ZnO/ crystals were prepared by a simple hydrothermal process and ultrasound pretreated hydrothermal process. ZnO/ urchins were fabricated in the precursor solution with []:[] ratio of 1:5 and rod structures were fabricated ratio of 1:1 and 1:3. Surface area ratio was increased by increasing the ratio of []. The sensitivity of sensors were highest at the []:[] ratio of 1:5 in ethanol, acetaldehyde, toluene, and nitric oxide.

Exhaled Breath Analysis of Lung Cancer Patients Using Metal Oxide Sensor

Breath tests are attractive since they are noninvasive and can be repeated frequently changing state of critically ill patients. Analysis of exhaled breath for recognition of human diseases using endogenous volatile organic compounds offers the possibility of noninvasive diagnosis. We investigated screening method of lung cancer. The system for screening of lung cancer was made by using metal oxide gas sensor array with solid phase microextraction(SPME) fiber. The system tested breath gas of lung cancer patient and health person and the breath gas was analyzed and compared with the components by GC-MS.

Facile Fabrication and Sensing Characteristics of TiO 2 Nanosheets Using Sonication

This study focuses on the fabrication of nanosheets and their gas sensor application. A simple sonochemical method is employed to fabricate the nanosheets. The obtained samples were investigated by transmission electron microscope(TEM) and X-ray Diffraction(XRD). The nanosheets were coated on substrates by a dropping method followed by heat treatment. The sensor responses to volatile organic compounds(VOCs) such as toluene, benzene, ethanol and acetaldehyde were studied. It was found that the nanosheets sensors are able to detect ppb-levels of VOC gases.

Breath analysis system for early detection of lung diseases based on multi-sensor array

Expiratory breath contains various VOCs(Volatile Organic Compounds) produced from the human. When a certain disease exists, the exhalation has specific VOCs which may be generated from diseases. Many researchers have been actively working to find different types of biomarkers which are characteristic for particular diseases. Research regarding the identification of specific diseases from exhalation is still in progress. The aim of this research is to implement early detection of lung disease such as lung cancer and COPD(Chronic Obstructive Pulmonary Disease), which was nominated on the 6th of domestic death rate in 2010, based on multi-sensor array system. The system has been used to acquire sampled expiratory gases data and PCA(Principle Component Analysis) technique was applied to analyze signals from multi-sensor array. Throughout the experimental trials, a clearly distinguishable difference between lung disease patients and healthy controls was found from the measurement and analysis of their respective expiratory gases.

Analysis of COPD Patient`s Exhaled Breath Using Sensor Array

The exhaled breath contains gases generated from human body. When disease occurs in the body, exhaled breath may include gas components released from disease metabolism. If we can find specific elements through analysis of the exhaled gases, this approach is an effective way to diagnose the disease. The lung function has a close relationship with exhalation. Exhaled gases from COPD (Chronic Obstructive Pulmonary Disease) patients can be analyzed by gas chromatography-mass spectroscopy (GC-MS) and a gas sensor system. The exhaled breath for healthy person and COPD patients had different components. Significantly more benzendicarboxylic acid was detected from COPD patients than in healthy persons. In addition, patients had a variety of decane. Phosphorous compounds with different isomers were detected from patients. The results obtained by gas sensor system were processed by PCA (Principal Component Analysis). The PCA results revealed distinct difference between the patients and healthy people.