A few years ago I touched upon a paper from Nature that discussed a new 3D printed technology that could detect when food was going off.  The device combined 3D printed plastic with embedded electronics to wirelessly monitor the freshness of the milk in your fridge.

Suffice to say, two years later we’re still waiting for such products to enter the market, but a recent project led by Clarkson University’s Silvana Andreescu shows the progress being made.  It describes a portable, paper-based sensor that can detect when food is spoiling, as well as things like contamination and cosmetic spoilage in an easy to understand manner.

“I’ve always been interested in developing technologies that are accessible to both industry and the general population,” Andreescu says. “My lab has built a versatile sensing platform that incorporates all the needed reagents for detection in a piece of paper. At the same time, it is adaptable to different targets, including food contaminants, antioxidants and free radicals that indicate spoilage.”

The system uses nanostructures to capture and bind to the compounds they’re looking for.  This sets the project apart from others, who use solutions that migrate on channels.  The system instead uses stable, inorganic particles that are redox active.  When these interact with the harmful substances, they change color.

What’s more, because the reagents needed to perform this are all contained within the paper, there’s no need for users to add anything to perform the tests.

The team believe the product has a wide range of possible applications.  Much of the early work has been around detecting antioxidants in tea and wine, but they’re confident it could be used in any scenario where antioxidants are being hunted.

It’s a fascinating project, and whilst it is still a little way from having something fit for market, it’s further evidence that such smart materials are getting closer.  Check out the video below to see the labels in action.