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Gas phase biomarkers for disease diagnostics by ion-mobility
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Tyagi, Heena (2023) Gas phase biomarkers for disease diagnostics by ion-mobility. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3977740
Abstract
The detection of Volatile Organic Compounds (VOCs) has shown great potential as a noninvasive and rapid diagnostic tool for early cancer and disease detection. The use of VOCs for early disease detection has several advantages and can provide valuable insights into disease pathophysiology. This PhD research aimed to investigate the presence of VOCs in urine samples and the development of chemical fingerprints for various cancers, namely, bladder cancer, colorectal cancer, prostate cancer and hepatocellular cancer, and diseases such as fibrosis and urinary tract infection. This study investigated the possibility of using analytical techniques such as Gas Chromatography-Ion Mobility Spectrometry (GC-IMS), Gas Chromatography-Time of Flight-Mass Spectrometry (GC-TOF-MS), and Electronic Noses (eNoses) for the identification of these biomarkers.
The study findings demonstrate the presence of particular VOCs in urine samples. We found that GC-IMS and GC-TOF-MS was able to distinguish between some of the cancers with 100% sensitivity and 100% specificity. During this research, a total of 46 VOCs were identified as relevant for the identification of these cancer groups, with some VOCs being specific to each type of cancer. 13 VOCs with the highest concentration in urine samples of bladder cancer patients were identified in the course of this study. The electronic noses utilized in this research were the AlphaMOS FOX 4000 and PEN3 eNose. The AlphaMOS FOX 4000 was able to distinguish between some of the cancer groups with 100% sensitivity and 100% specificity. Although, PEN3 eNose did not exhibit 100% sensitivity in distinguishing between the different cancer groups, it still demonstrated high levels of sensitivity and specificity.
Overall, the study contributes to the advancement of research on the detection of VOCs and provides insights into the potential for using analytical techniques for the detection of VOCs in urine samples. However, there are some limitations to these technologies such as some of them require specialized training and expertise to operate and interpret results accurately and the cost of some of these technologies can be high, making them less accessible. Another limitation is that the detection of VOCs can be affected by factors such as sample collection, handling, and storage, which can impact on the accuracy of results.
The second aim of this research presents the development of an in-house device based on Photo Ionisation Detector (PID) for the detection of VOCs. The thesis focuses on the xxii evaluation of the performance of the developed PID+ based device for detecting ISB. Throughout this thesis, we have examined the electronics of PID+. Experiments were conducted to assess the performance of the PID+ at various flow rates, ISB (Isobutylene) gas concentrations, bias voltages of detector plates, and amplifier circuit gains.
The results of the study demonstrate the feasibility and efficacy of the developed device in detecting ISB with high response. It was observed that increasing the flow rate of the sample gas has the potential to improve the response time of the detector. Additionally, it was observed that the concentration of the target VOCs, in this case ISB gas, was a crucial factor that affected the response of the detector, with higher concentrations resulting in higher sensitivities. However, it was noted that elevating either the flow rate or the concentration of the target VOCs beyond a certain threshold could lead to the saturation of the output. During the testing of the two versions of PID+, the performance of the PID+ was significantly improved. Nevertheless, more extensive research is required to verify the validity of the results of this study with respect to various VOCs.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry Q Science > QH Natural history Q Science > QP Physiology R Medicine > RA Public aspects of medicine R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer) |
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Library of Congress Subject Headings (LCSH): | Volatile organic compounds -- Health aspects, Biochemical markers, Cancer -- Diagnosis, Ion mobility spectroscopy, Gas chromatography | ||||
Official Date: | April 2023 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | School of Engineering | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Covington, James A., 1973- | ||||
Format of File: | |||||
Extent: | xxvii, 256 pages : colour illustrations | ||||
Language: | eng |
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