You might have missed: 3D printed “finger”; egg cell vortexes; embroidered sensors; and Borderlands Science

3D printed prototype “finger” with rigid bones and flexible flesh

Engineers designing soft robotics or wearable devices often turn to elastomers – synthetic polymers that can be manufactured with a range of mechanical properties. But making elastomers that can be shaped into complex 3D structures that go from rigid to rubbery has been unfeasible until now.

“Elastomers are usually cast so that their composition cannot be changed in all 3 dimensions over short length scales,” says Esther Amstad, head of the Soft Materials Laboratory at the Swiss Federal Institute of Technology Lausanne.

“To overcome this problem, we developed DNGEs: 3D-printable double network granular elastomers that can vary their mechanical properties to an unprecedented degree.”

Photograph of blue gloved hands holding a small transparent tube "finger" with 3 dark pink rods inside.
DNGE prototype ‘finger’ with rigid ‘bones’ surrounded by flexible ‘flesh’. Credit: © Adrian Alberola

They used different formulations of DNGEs to print a prototype finger containing 3 rigid 0.8 cm long “bones” surrounded by a soft, elastic skin. The research has been published in the journal Advanced Materials.

DNGEs have potential applications in devices for motion-guided rehabilitation where the ability to support movement in one direction, while restricting it in another, could be highly useful. 

Amstad says that the lab is already working on the next steps toward developing these applications by integrating active elements – such as responsive materials and electrical connections – into DNGE structures.

Cracking the mystery of swirling vortexes inside egg cells

Female reproductive egg cells, or ova, are often several to hundreds of times the size of a typical cell.

This means that while it takes only 10 to 15 seconds for a typical protein molecule to make its way from one side of a typical human cell to the other via diffusion, the same process would take an entire day in a fruit fly egg cell – much too long for the cell to function properly.  

Scientists have long known that maturing egg cells, called oocytes, generate internal, twister-like fluid flows to stir things up internally and aid in the transport of nutrients. But exactly how those flows arise in the first place has been a mystery.

Now, new experiments on fruit fly egg cells have revealed that these flows arise from the motion of thousands of microtubules – flexible filaments that line the inside of a cell – as they buckle under the forces exerted by molecular motors.

“Now that we know how these twisters form, we can ask deeper questions, like how do they mix the molecules inside the cell?” says Reza Farhadifar, research scientist at the Flatiron Institute’s Center for Computational Biology in the US, and co-author of the new paper in Nature Physics.

“This opens a new dialogue between theory and experiment.”

This simulation shows how the movement of microtubules creates swirling flows in a cell. Credit: S. Dutta et al.

Using embroidery techniques to turn fabric into a “clickable” button

A new study has combined 3D embroidery techniques with machine learning to create a fabric-based sensor that can control electronic devices through touch.

The device is made up of an embroidered pressure sensor and a microchip which processes and distributes the data collected by the sensor.

The triboelectric sensor powers itself with electric charge generated from friction between its multiple layers. It is made from yarns consisting of 2 triboelectric materials, one with a positive electric charge and the other with a negative charge, which were integrated into conventional textile fabrics using embroidery machines.

Machine learning allows the embroidered sensor to recognise simple finger gestures for controlling interfaces, such as a music playing mobile app, setting and inputting passwords, and video games.

The research is published in the journal Device.

Researchers use a fabric-based triboelectric touch sensor to control a video game. Credit: NC State University

Millions of Borderlands 3 gamers advance biomedical research

More than 4 million gamers playing a citizen science mini-game within the successful video game Borderlands 3 have helped reconstruct the microbial evolutionary histories of bacteria in the human gut.

“In half a day, the Borderlands Science players collected 5 times more data about microbial DNA sequences than our earlier game, Phylo, had collected over a 10-year period,” says Jérôme Waldispühl, an associate professor in the School of Computer Science at McGill University in the US, and senior author on a paper describing the research in Nature Biotechnology.

Illustration of a borderlands science minigame
Credit: Gearbox

Since its initial release on 7 April 2020, players have solved more than 135 million science puzzles by aligning rows of tiles which represent nucleotides – the genetic building blocks of DNA – of different microbes.

Not only have the gamers improved on the results produced by existing programs used to analyse DNA sequences, but they are also helping lay the groundwork for improved AI programs that can be used in future.

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