Smart masks to fight COVID-19, strips that detect spoiled food, pills for collecting gut samples and keyboards printed on our favourite material… paper! Catch up on the monthly news from the field of printed electronics in our September digest below.

Smart masks to fight COVID-19

We’re using face masks to avoid contagion of SARS-CoV-2 in many countries. However, experts say that we reuse them more than we should. Do you know when it’s time to change your mask? Physicians and engineers in the Netherlands are working on a solution. They’re developing a smart mask that uses flexible sensors printed into the fabric which monitor the wearer’s body activity and vital signs, such as temperature, breathing and humidity. That way, the sensors can indicate if the mask is functioning properly or needs replacing. What’s more, they can also tell us if the wearer is healthy!

Silk strips that detect spoiled food

Much food is wasted because we don’t know wheter it’s spoiled or not. Engineers from MIT have developed a smart velcro strip that can inform costumers if food has spoiled or is contaminated. The sensor is printed with two types of ink: one of them changes colour when in contact with fluid of a certain pH range, indicating the food is spoiled; the other turns coloured when it senses contaminating bacteria. But what is really impressive is that this food sensor is made from silk, which is edible, nontoxic, can be used as a food ingredient, and is mechanically robust enough to penetrate through a large spectrum of tissue types, like meat, peaches, and lettuce. “A technology like this would give confidence to the end user to not waste food,” explain the authors.

This smart strip checks for food spoilage. © MIT

“Gutoscopy”: smart pills to collect gut samples

Smart pills are tiny devices that can be swallowed and perform different functions as they move along the gastrointestinal tract. They can use biosensors to collect information such as pressure, pH and temperature data and there are other types that collect samples from inside the body. These “gutoscopy” capsules are made of nontoxic 3D-printed resin that dissolve at a specific pH within the gut and release a gel that collects samples as it moves through the bowel. Finally, a change in pressure forces the capsule to close and researchers can then open the capsule to analyse the samples. That way, scientists avoid invasive procedures that require surgery or catheter usage. Read more about this amazing invention here!

Turning a sheet of paper into a keyboard

3D technology has shown it can print almost anything you can imagine, even electronic devices. But this technology is even more surprising when it uses such common materials as paper. That’s what we’re doing at INNPAPER, and we aren’t the only ones. Scientists from the Purdue University in the US have created a working keypad and controller, printed directly onto a sheet of paper. They were able to use that piece of paper to type letters onto a screen and swipe a finger across a printed volume control. What’s more, the device they have created is self-powered, as it generates electricity from contact with the finger of the person operating it! According to the authors, this experiment is part of an exciting new wave of flexible computing.