The researchers made sensors from porous thin films of organic conductive plastics with the goal of portable, disposable devices for medical and environmental monitoring.
[Image from L. Brian Stauffer/University of Illinois]
The device is made from small, thin, organic plastic that is in the shape of a square. The researchers have so far been able to monitor ammonia in patients’ breath, which can be an indicator of kidney failure.
“In the clinical setting, physicians use bulky instruments, basically the size of a big table, to detect and analyze these compounds. We want to hand out a cheap sensor chip to patients so they can use it and throw it away,” said Ying Diao, a professor of chemical and biomolecular engineering at the University of Illinois and a researcher on the study, in a press release.
Previous organic semiconductors were not sensitive enough for gas sensing and were unable to detect disease markers in the breath. Diao and the research team concluded that reactive sites in the sensors were inside the plastic film and not on the surface.
“We developed this method to directly print tiny pores into the device itself so we can expose these highly reactive sites,” Diao said. “By doing so, we increased the reactivity by 10 times and can sense down to 1 part per billion.”
The researchers wanted to focus on using the sensors to detect ammonia in a patient’s breath to determine if they had the early warning signs of kidney disease. The sensor’s material was proven to be highly sensitive to ammonia, but not any other compounds in the breath.
If they changed the composition of the sensors, the researchers found that they could create devices that could detect other compounds in the breath. To test that theory, Diao and her team were able to modify the sensors to detect formaldehyde.
“We would like to be able to detect multiple compounds at once, like a chemical fingerprint,” said Diao. “It’s useful because in disease conditions, multiple markers will usually change concentration at once. By mapping out the chemical fingerprints and how they change, we can more accurately point to signs of potential health issues.”
The study was published online in the journal Advanced Functional Materials.
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