Wearable Sensor Facilitates Environmental and Health Monitoring

A novel gas sensing platform can detect chemical and biological agents that may damage the nerves or lungs, according to a new study.

Under development at Hebei University of Technology (Tianjin, China), South China University of Technology (SCUT; Guangzhou, China), Pennsylvania State University (PSU; Hershey, USA), and other institutions, the gas sensing platform is based on a highly porous laser-induced graphene (LIG) pattern that consists of the actual sensing region and a serpentine interconnected region coated with silver. When an electrical current is applied to the silver, the gas sensing region heats up, improving sensing performance of the interdigitated electrode (IDE) nanomaterial sensors.

The nanomaterials used in the sensing platform are reduced graphene oxide and molybdenum disulfide, a combination of the two, or a metal oxide composite consisting of a core of zinc oxide and a shell of copper oxide. These material represent the two major classes of widely used gas sensor materials - low-dimensional and metal oxide nanomaterials. By dispersing nanomaterials with different selectivity in the sensing region, a range of various gaseous components could be potentially deconvoluted. The study was published in the January 2020 issue of Journal of Materials Chemistry A.

“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,” said senior author Huanyu Cheng, PhD, of 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.”

“In this paper, we showed that we could detect nitrogen dioxide produced by vehicle emissions. We can also detect sulfur dioxide, which, together with nitrogen dioxide, causes acid rain. All these gases can be an issue in industrial safety,” said co-lead author Ning Yi, MSc, of PSU. “The next step is to create high-density arrays and try some ideas to improve the signal and make the sensors more selective. This may involve using machine learning to identify the distinct signals of individual molecules on the platform.”

Related Links:
Hebei University of Technology
South China University of Technology
Pennsylvania State University