Paper electronics directly drawn on a paper cup, a milk carton and a meat price tag. Credit: Applied Materials Today (2022). DOI: 10.1016/j.apmt.2022.101589
The environmental consequences of non-biodegradable food packaging have led to an increase in the production and availability of eco-friendlier paper alternatives. In situ food monitoring systems, while important for preventing food poisoning, can contribute to food packaging waste due to the attachment of sensors that are made from non-biodegradable materials. Researchers from Seoul National University, Hanyang University and the Georgia institute of Technology have now developed a food quality sensing system based on laser-induced graphene, which can be fabricated directly on a biodegradable material and detect both food temperature and food spoilage.
The research team developed technology that allows graphene to be synthesized through a local thermal reaction by irradiating a laser on a carbon-based paper substrate. The laser-induced graphene has excellent electron mobility, which enables it to sense temperature; it also possesses a highly porous structure and high specific surface area, which allows the sensor to detect concentrations of gas molecules, such as gasses emitted during food spoilage. The direct laser irradiation method works on any type or structure of commercial paper, meaning a sensor circuit can be fabricated on biodegradable food packaging for real-time in situ monitoring of food quality. Additionally, data from the sensor can be transmitted wirelessly to a mobile phone.
The researchers demonstrated the potential application of their sensing system in real-life situations by fabricating sensors on commercially available milk cartons, paper cups and price tags on meat packaging. The graphene sensors allowed the team to monitor the temperature of liquids in the paper cups as well as monitor the freshness of meat over time, with real-time results continuously transmitted to a mobile phone. The technology presents a potential smart system for assessing food safety before intake, protecting consumers from food poisoning while also reducing concerns about material waste and environmental harm. This study was published in Applied Materials Today.
“This achievement is research that fits the global Green New Deal trend, and is expected to provide valuable assets and insight into the development of technologies that can solve environmental and safety related issues in the food industry,” said co-corresponding author Seung Hwan Ko, a professor in the Department of Mechanical Engineering at Seoul National University. “And further from the food industry, it is expected to be used in various industrial fields as an eco-friendly and biodegradable material based temperature and gas sensor.”