Skip to Main Content
 

Global Search Box

 
 
 
 

Files

ETD Abstract Container

Abstract Header

Optical Chemical Sensing Device for In-situ Non-Invasive Gas Monitoring

Badmaarag, Ulzii-Orshikh

Abstract Details

2020, MS, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
A highly selective and rapid optical sensing approach was previously demonstrated as a potential non-invasive medical diagnostic method for real-time detection of acetone as a biomarker in human breath to determine the blood glucose level of the patients. The approach employed a perfluorosulfonic acid (PSA) membrane catalyst containing immobilized reagent which drove a colorimetric response to the presence of target molecules as the optode. The success of the previous work provided strong rationale to develop a prototype device for non-invasive breath analysis in practical clinical settings. The focus of this work was to evaluate the fundamental operational characteristics of such an optical sensing prototype during real time acetone detection in clinical application. This was achieved through theoretical modelling and experimental validation of these theoretical results. Furthermore, as a part of this work, the cause and effect relationship of raw materials selection for preparation of the membrane optode and its optical response interferences have been identified. In addition, the storage conditions of the membrane were studied to determine the durability of membrane for further studies. As a result, the optimized preparation and storage conditions of the PSA membrane were provided in this work. Mathematical modeling of the optical response entailed classic mass transport modeling of both acetone flow through sample chamber and membrane optode of the prototype as well as the evolution of acetone concentration in exhaled human breath from capillaries in the lungs. Calibration experiments were conducted to confirm this theoretical model. Calibration results indicated that humidification in the device sample chamber is controlling membrane diffusion through the membrane. As a result, the optode response to acetone exposure was found to be controlled by acetone mixing in the sample chamber rather than membrane resistance as long as the membrane was fully humidified and sufficiently thin. This finding simplifies correlation of optode response to patient metabolic and physiological processes. Increasing the membrane humidification period and reducing the thickness of membrane to 1 mil yielded a significant improvement in the correlation of experimental time dependence to the predicted time dependence. To simulate the real-time breath analysis, calibration data was collected for 40 seconds. This enables the use of calibration results in real-world clinical application. Small-scale clinical trials were conducted to quantify the time evolution of acetone concentration in human breath. In addition to diabetic patients as previous studies had been focused on, patients with a history of wide range of diseases such as chronic respiratory disease (COPD), asthma, mastocytosis, angioedema, hereditary angioedema (HAE) and allergies contrasted to a healthy control group of patients were randomly recruited to participate in this study to correlate the breath acetone present to lung vascular permeability. Significant variability was observed for clinical data that, unlike previous work, did not permit correlation between breath acetone concentration and blood glucose levels of the patients. This variability is sown to arise from improper humidification of the membrane optode, consistent with our calibration studies. Finally, the required humidification conditions for the prototype were identified for implementation in future clinical trials.
Anastasios Angelopoulos, Ph.D. (Committee Chair)
Jonathan Bernstein, M.D. (Committee Member)
Aashish Priye, Ph.D. (Committee Member)
79 p.

Recommended Citations

Citations

  • Badmaarag, U.-O. (2020). Optical Chemical Sensing Device for In-situ Non-Invasive Gas Monitoring [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583155117533193

    APA Style (7th edition)

  • Badmaarag, Ulzii-Orshikh. Optical Chemical Sensing Device for In-situ Non-Invasive Gas Monitoring. 2020. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583155117533193.

    MLA Style (8th edition)

  • Badmaarag, Ulzii-Orshikh. "Optical Chemical Sensing Device for In-situ Non-Invasive Gas Monitoring." Master's thesis, University of Cincinnati, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583155117533193

    Chicago Manual of Style (17th edition)