Dr Sina Naficy

Food waste is a major environmental and social problem, with studies showing that more than one-third of global food is lost along the supply chain. It is estimated that two-thirds of food waste could be avoided if there were food sensors capable of evaluating the quality of the food.

That is why University of Sydney Research Fellow Dr Sina Naficy developed an entirely new class of 3D-printed electrical gas sensors that detect gases generated by bacteria in packaged food.

This new technology can be produced at near-zero cost and exploits the hygroscopic properties of cellulose, which absorbs large amounts of water. This enables the use of wet chemistry for sensing water-soluble gases in flexible cellulosic substrates such as paper.

These cellulosic sensors are flexible, and their fabrication process is scalable.

Naficy conceptualised and executed a method for 3D printing these sensors on a large scale while enhancing their sensing selectivity. The innovation lies in using cellulose, the most abundant biopolymer, to fabricate highly value-added products — sensors — by manipulating their chemistry.

Naficy achieved this goal by impregnating specific gas-affined polymers and molecules. Naficy’s technique 3D prints the cellulosic inks on any flexible plastic substrate by tuning their rheological and gelation properties.

“Incorporating sensors into packaged food — fresh or processed — will provide real-time information about the actual state of the food, leading to better decision making,” he said.

“The data-supported decisions based on information gathered by sensors in the packaging will enhance shelf life, efficiency, safety and quality of food, and will reduce food waste.”

Naficy is focusing on expanding the diversity of the sensors and their target analytes. This is an important part of the University of Sydney’s research portfolio on flexible food sensors for packaging.