Gas-based chemical sensors have proven invaluable for investigating the underlying chemical configuration of a particular odorant. Technologies such as gas chromatography-mass spectrometry and hyphenated ion mobility spectrometry have elucidated numerous causal factors and biochemical pathways contributing to a variety of healthy and pathologic conditions. Nevertheless, these technologies face innate challenges that have precluded their adoption and implementation in the clinical environment. As a result, a considerable amount of research and development has been geared towards fabricating cheap, easy-to-use, and highly portable electronic noses. These devices have demonstrated excellent potential for applications such as environmental monitoring, food analysis, and forensic science. Moreover, innovations in nanotechnology and other materials science fields have spurred the ideation and creation of highly efficient electronic noses. However, the broad range and low concentrations of chemical metabolites observed in breath profiles, hinders their use as medical diagnostics for complex diseases. Here, this work proposes a novel technology utilizing biologically based chemical biosensors to accurately characterize the volatile profiles associated with pathological disease states, especially that of cancer. The development of this powerful and efficient gas-sensing system has the potential for use in a variety of real-world contexts, including homeland security, law enforcement, and medicine.It is well known that the presence of disease alters underlying biochemical processes, thereby influencing metabolic byproducts and the volatile chemicals excreted via the breath. Existing manmade chemical sensors as medical diagnostics lack the ability to differentiate the breath profiles of healthy individuals from those with complex diseases. Chapter 1 investigates the field of volatolomics as a whole, including the gas-based identification of 'simple' diseases and the application of state-of-the-art sensor technologies to diagnose complex pathologies. In chapter 2, the methodology for all experiments involving this novel gas-based biosensor in the context of disease diagnosis is discussed. Chapters 3, 4, and 5 detail applied research which validates the biosensors' powerful abilities to differentiate chemicals and chemical profiles. This work serves to establish its potential as a non-invasive medical diagnostic using biological matrices, such as breath profiles. Finally, chapter 6 discusses the current limitations of the proof-of-concept technology as well as modifications that will mitigate such limitations and aid in the creation of an effective state-of-the-art breath-based medical diagnostic.
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