Could use-by dates be past their use-by date?

Electronic circuits could take the guesswork out of knowing whether milk is actually out of date or whether it has a day or two left - no smelling required.

Researchers from Nanyang Technological University (NTU) in Singapore have successfully printed complex electronic circuits using a common t-shirt printer. The electronic circuits can be printed in layers on top of everyday flexible materials such as plastic, aluminium foil and even paper.

“This means we can have smarter products, such as a carton that tells you exactly when the milk expires, a bandage that prompts you when it is time for a redressing and smart patches that can monitor life signals like your heart rate,” said Associate Professor Joseph Chang from NTU’s School of Electrical and Electronic Engineering, who led the research group.

“We are not competing with high-end processors like those found in smartphones and electronic devices. Instead, we complement them with cheaply printed circuits that cost mere cents instead of dollars, making disposable electronics a reality.”

The key difference between Professor Chang’s method and the other types of printed electronics is that it is fully additive, which makes it very eco-friendly. The circuits are printed entirely without the use of any toxic chemicals or oxidising agents.

“Our innovative process is green, using non-corrosive chemicals. It can be printed on demand when needed within minutes. It is also scalable, as you can print large circuits on many types of materials, and most importantly, it is low cost, as print technology has been available for decades,” said Professor Chang.