You may have missed… 3D-printing ink for making lab-grown meat, gel-bots, starch-based wearable sensors, and wood-eating clam poop.

New plant-based 3D-printing ink for making lab-grown meat more cost-effective

For the environmental or animal welfare-minded consumer, lab-grown meat offers a promising alternative to traditional livestock.

Chinese researchers have now found a way to use plant-based food waste to reduce the high production costs associated with lab-grown meat.

To produce lab-grown meat, animal muscle stem cells are grown on a scaffold which improves the environment for the cells and allows suitable texture and structure to be generated.

Without it the lab-grown meat would resemble lumpy mashed potatoes.

Until now, these scaffolds have been made using an emerging 3D-printing technology using edible ink made from animal products, like gelatine and collagen, or synthetic materials. But these are inks are expensive to produce.

Now, scientists have developed a new, edible, plant-based ink, derived from food waste – such as cereal husks – that can be fully absorbed into the lab-grown meat product and is cheap to produce.

“This is a novel and disruptive idea to mass produce cultured meat. Using nutrients from food waste to print scaffolds not only uses and increases the value of the food waste but also alleviates the pressure on the environment from animal agriculture,” says Professor Jie Sun from Xi’an Jiaotong-Liverpool University, China.

The study has been published in the journal Advanced Materials.

A robot that does ‘the worm’ when the temperature changes

A new gelatinous robot that crawls, powered by nothing but temperature change, has been reported in a new study in Science Robotics.

The soft-robot is made from a water-based gel that swells or shrinks in response to temperature. The team of researchers has demonstrated that this can be manipulated to move the robot forward and backward on flat surfaces with an undulating, wave-like motion.

“It seems very simplistic, but this is an object moving without batteries, without wiring, without an external power supply of any kind – just on the swelling and shrinking of gel,” explains senior author David Gracias, a professor of Chemical and Biomolecular Engineering at Johns Hopkins University in the US.

“Our study shows how the manipulation of shape, dimensions and patterning of gels can tune morphology to embody a kind of intelligence for locomotion.”

The researchers see a range of potential applications – from moving through the human body to deliver targeted medicines to patrolling and monitoring the ocean’s surface.

Using starch to make flexible, wearable electronic sensors

Scientists have developed a new starch-based polymer that makes it possible to create a fully biodegradable soft material for sensors.

Soft, stretchable polymers are used to make various kinds of electronic devices – from the sensors in smart-watches to the screen on your smartphone. But these soft materials are often made from mixtures of polymers which are difficult to purify and recycle, and as a result they’re dumped in landfills with the sensor’s toxic metal components.

This kind of electronic waste is becoming a serious problem.

“To create a biodegradable polymer, we started out with a backbone of starch-derived dextrin carbohydrates,” explains first author Dr Xiaohong Lan, a postdoctoral researcher at the University of Groningen Polymer Science group in the Netherlands.

Sugar polymers, basically.

“Most polymer backbones contain chemical bonds, which are very strong. The dextrin backbone can be degraded by natural enzymes that are present in soil,” Lan says.

The research has been published in ACS Applied Materials & Interfaces.

Wood-eating clams use their excrement to dominate their habitat

Deep in the ocean tiny clams with shells only as big as a pea are boring into pieces of sunken wood, eating and building their homes.

A new paper in Marine Biodiversity has found that one group of these clams has evolved a unique (and kind of gross) way to keep their precious wood all to themselves: building chimneys made of feaces.

Scientists can put wood on the sea floor and sometimes return to find it so bored-through that it’s possible to crumble by hand.

Researchers have now found that this extra-chewed-up wood is all thanks to the same group – Xylophagaids. As these clams dig and move their boreholes in the wood, they fill the space around them inside the holes with their own faeces.

“They don’t do it on purpose, their anatomy makes them do it,” says lead author Dr Janet Voight, Associate Curator of Invertebrate Zoology at the Field Museum in the US.

The clams’ siphons, tubular appendages for taking in water to get oxygen and expelling waste, stick out behind them as they bore.

“In most wood-boring clams, these two ‘in and out’ siphons are equal in length and stick out into the water column,” says Voight. “But in these related hyper-nasty borers, the siphon for expelling de-oxygenated water and faeces is short; it stays inside the borehole in the wood.”

The researchers think that the “poop chimneys” may serve as a beacon for other members of their species to join them on their wood. And adaptions, such as an unusual tolerance for low oxygen and a mucosal lining of the chimneys, allow them to survive in conditions that would make non-related wood-boring clams sick. This means they can live unbothered by competitors.