Laser technology monitors heart health through the breath

Tuesday, Aug 12, 2014

New research from Princeton Engineering looks at monitoring patient health through breath.

Princeton Spectroscopic Sensor Development Team: Yin Wang, Michael Nikodem, Eric Zhang and Gerald Wysocki

A short film by:Volker Steger
Editor: Jamin Benazzous
Producer: Teresa Riordan

Published on Jun 26, 2014

Gerard Wysocki, assistant professor of electrical engineering at Princeton University, discusses his laser technology for detecting nitric oxide in the breath as a way for doctors to monitor patient health. Wysocki is testing the technology with Professor Raed Dweik of the Cleveland Clinic.


GERARD WYSOCKI: Our breath is actually a mixture of many gasses. What is important is that some of these gasses might be really important for our health. I'm Gerard Wysocki, and I'm Assistant Professor in the Electrical Engineering department at Princeton University.

Why nitric oxide is important? It's probably because of its important function, of being a signaling molecule in the cardiovascular system. It takes a lot of different pathways through our body. For example, if you have inflammation in your body, this inflammation will be producing nitric oxide, that will be detectable in a gas phase.

We use lasers to perform optical spectroscopy. This is a method that gives you a very high specificity, and we basically see only nitric oxide, and we don't see many other species. Those millions of species that you can find in your breath, are invisible to our analyzer, and that's the advantage.

If you put nitric oxide in a magnetic field, you align those molecules in the space. And then when they interact with the laser light, they do it slightly different than any other molecule in that mixture. In our breath we usually observe anything between single parts per billion levels, to maybe 100 parts per billion levels for people who produce a lot of NO due to inflammation. People with asthma usually produce higher levels.

And the analyzer that you will be using to detect it has to be very sensitive, to look at such a small minute amount of nitric oxide in the breath. That's the main difficulty in measuring important molecules in breath. The optical configuration is very simple. We have three major elements, the laser a gas cell between two polarizers, and a photo detector.

In this kind of instrumentation, in order to improve sensitivity, we have to suppress the noise. And we came up with a new method of suppressing the noise, by modulating the laser at really high frequencies, where the noise is much lower. And then subsequent modulation at that high frequency allows us to reach fundamental quantum noise levels, which allows to perform this measurement at really high sensitivities.

My graduate student Yin Wang is currently working with Doctor Raed Dweik from Cleveland Clinic, on application of our analyzer to detection of nitric oxide in breath, urine, and blood samples. In the clinical environment, research that is currently ongoing requires this type of analyzers to look at nitric oxide in many different forms. We are the first to actually be able to measure nitric oxide isotopes in breath, urine, and blood samples simultaneously.

And this particular moment, I think this technology is ready for research in clinical environments. The next stage will be to improve the compactness, improve the overall easiness of use, and use it in the doctor's office. I think it would be great if you go to the doctor's office, and he tells you what's good or bad about your body, to make little adjustments in the next couple of months. And maybe come back and take another test, without losing a drop of your blood.