Detection of Pneumonia Volatile Organic Biomarkers Via Nanotube Sensing Platform
Authors: Saffary Yalda , McKinnon Lani , Willis Christina Nicole , Carlson Krista , Mohanty Swomitra K. 
Published: February 2020

Infectious microorganisms are known to release volatile organic biomarkers (VOBs) that can be found in human breath, urine, blood, etc. Pneumonia, which is caused by a consortium of microorganisms residing in the lungs, is one of the deadliest infectious diseases in the world. It is responsible for 80% of deaths in children under 2 years1. Having a point of care, inexpensive device that can detect pneumonia in less than 20 minutes would make considerable improvement in disease detection. One proposed method of detecting pneumonia is measuring the presence and concentration of VOBs in the breath. At specific biased voltages, metal functionalized titanium dioxide sensors have shown promising results in the detection of tuberculosis from breath in our previous work2-3. Pneumonia microorganisms release several VOBs or will increase the concentration of some VOBs that are present in breath in low amounts. Heptane, 2-methyl butane, furan, ethylbenzene and ethanol are some examples of non-polar and polar VOBs present the breath of pneumonia patients at significant concentrations4. Depending on the polarity of the VOB metal functionalized or non-functionalized titanium dioxide nanotubes base sensors at specific based voltage will respond to the presence of these biomarkers. Figure 1 presents the preliminary sensor response to pneumonia biomarker, heptane. The result was conducted using a non-functionalized titanium dioxide sensor at a low biased voltage. The sensor was exposed to nitrogen gas as a negative check and nitrogen that was bubble through heptane using amperometric testing method. Initially the sensor was exposed to nitrogen followed by two heptane exposure then one more nitrogen exposure to confirm the negative check. Various range of biased voltages from -2 to 2 V was tested with 1.5V showing response to heptane. As shown in figure 1, when the sensor was exposed to heptane there is an increase in current whereas nitrogen exposure reduced the current. The current calculations are normalized to the background currents. Metal functionalized sensors would react to the presence of VOBs at lower biased voltages.
Overall, the proposed method of disease detection device would help diagnosing pneumonia painlessly that does not require highly qualified technicians to perform. Additional results of the structured solid stat sensor interactions with polar and non-polar pneumonia VOBs using various electrochemical methods will be shown in the presentation.

United for Lung Health. Fact Sheet: World Pneumonia Day 12 November 2018.

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Figure 1