A highly sensitive, wearable gas sensor for environmental and human health monitoring may soon become commercially available, according to researchers at Penn State and Northeasten University.

The sensor is more advanced than existing wearable sensors due to its self-heating mechanism that enhances sensitivity, which allows for quick recovery and reuse of the device.


Source: Cheng Lab/Penn State

“People like to use nanomaterials for sensing because their large surface-to-volume ratio makes them highly sensitive,” said Huanyu Cheng, Assistant Professor of Engineering Science and Mechanics and Materials Science and Engineering at Penn State. 

“The problem is the nanomaterial is not something we can easily hook up to with wires to receive the signal, necessitating the need for something called interdigitated electrodes, which are like the digits on your hand.”

Cheng and the team used a layer to pattern a highly porous single line of nanomaterial for the sensor that detects gas, biomolecules, and in the future, chemicals.

In the non-sensing portion of the device platform, the team created a series of serpentine lines coated with silver. When electrical current is applied to the silver, the gas sensing region will heat up due to significantly larger electrical resistance, eliminating the need for a separate heater.

“Using a CO2 laser, often found in machine shops, we can easily make multiple sensors on our platform. We plan to have tens to a hundred sensors, each selective to a different molecule, like an electronic nose, to decode multiple components in a complex mixture.”

Ning Yi, a Doctoral Student in Chen’s Lab and Co-Lead Author of the paper posted online, said, “In this paper, we showed that we could detect nitrogen dioxide, which is produced by vehicle emissions.”

“We can also detect sulphur dioxide, which, together with nitrogen dioxide, causes acid rain. All these gases can be an issue in industrial safety.”

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