Science Buddies: "Ask an Expert"

Hi,

I am constructing an electronic nose as an invention to detect VOCs (such as certain alcohols and aldehydes) in a person's breath to determine the presence of infectious diseases in children recovering from chemotherapy. However, I am not sure how to test my invention. I have been considering buying E. coli K-12 and testing the VOCs it emits since E. coli is a bacterium that commonly infects chemotherapy patients. However, this would not account for the other factors that cause the production of VOCs in breath that my invention would have to account for. I have also been considering using different food items or plants and exposing them to mold to test whether my invention would be able to differentiate between the moldy food/plants and the food/plants not exposed to mold. Unfortunately, I am not sure if this would be an accurate model of what I am trying to test. Lastly, I've been trying to find ways to test actual human breath but I have not found any breath samples of infected patients that I could purchase and I am not too sure how I can receive breath samples otherwise. My teacher also does not recommend studies on humans as there are hundreds of factors (age, diet, lifestyle, etc.) that need to be taken into account.

I would really appreciate if I could receive some inputs on how I could receive breath samples and test them or better yet, if I could somehow accurately model a patient's breath and test that instead. I greatly appreciate your advice and will take all suggestions into consideration.

Thanks,
winner27

Hi,

That's an intriguing idea you have to monitor a person's health by analyzing VOCs in their breath. How will you assay and identify the VOCs? How much breath do you need to do an assay? Do you actually collect a breath sample or can you have the person breathe into the analyzer and get a readout in real time?

You could analyze your own breath at various times and see if the results correlate with what you ate or drank, whether you brushed your teeth or if there were traces of a particular kind of mouthwash. Maybe all you need right now is proof-of-concept--that your analyzer is able to reproducibly and sensitively identify VOCs in a person's breath. That in itself would be a good accomplishment, and later you could expand the project to focus on those VOCs that indicate disease.

Please post again with more details about how you would do the breath analysis and we will try to help you make a project out of your invention.

Sybee