Getting a grip with “necrobotic” spiders
Mechanical engineers have essentially turned dead spiders into “claw machines” and used them as mechanical grippers to pick up objects heavier than themselves, according to a new study in Advanced Science.
“It happens to be the case that the spider, after it’s deceased, is the perfect architecture for small scale, naturally derived grippers,” says senior author Daniel Preston, assistant professor of Mechanical Engineering at Rice University in Texas, in the US.
Spiders use hydraulics to move their limbs; the prosoma chamber near their heads contracts to send blood to limbs (which forces them to extend) and when the pressure is relieved the legs contract.
Using wolf spider cadavers, they tapped into this chamber with a needle to deliver a minute amount of air, activating and extending the legs almost instantly.
But what on Earth are the applications for these so-called spidery “necrorobots”?
According to Preston: “there are a lot of pick-and-place tasks we could look into, repetitive tasks like sorting or moving objects around at these small scales, and maybe even things like assembly of microelectronics.
“Also, the spiders themselves are biodegradable. So we’re not introducing a big waste stream, which can be a problem with more traditional components.”
Extending the shelf-life of vaccines with hydrogel
From the time of manufacture to administration, most vaccines need to be kept within strict temperature ranges but maintaining this along the supply chain can be incredibly challenging, especially in regions where there is limited transport infrastructure and unreliable access to electricity.
Because proteins in a vaccine clump together irreversibly when exposed to certain temperatures –like how the proteins in an egg change structure permanently when cooked – the hydrogel encapsulates the proteins to keep them separated. A molecular Tupperware if you will.
Instead of the traditional 2 to 8°C temperature range, encapsulation allows for vaccines to remain stable at 25 to 65 °C.
Hyaluronic acid awakens stem cells to repair damaged muscle
Scientists have identified hyaluronic acid, a naturally occurring substance often used in cosmetics and injections for osteoarthritis, as a key molecule that manages the cell communication which controls muscle repair.
How exactly stem cells work together with immune cells to repair damaged muscle – by removing dead tissue before making new muscle fibres – has remained unknown until now.
“Our study shows that muscle stem cells are primed to start repair right away, but the immune cells maintain the stem cells in a resting state while they finish the clean-up job. After about 40 hours, once the clean-up job is finished, an internal alarm goes off in the muscle stem cells which allows them to wake up and start repair,” explains senior author Dr Jeffrey Dilworth, a senior scientist at the Ottawa Hospital Research Institute and the University of Ottawa, Canada.
Dilworth and his team identified hyaluronic acid as the key molecule in this internal alarm clock. When muscle damage occurs, stem cells start producing and coating themselves with hyaluronic acid. Once that gets thick enough, it blocks the sleep signal from the immune cells and causes the muscle stem cells to wake up.
The study has been published in Science.
Teaching microrobots to swim and navigate with AI
According to the study published in Communications Physics, they showed that a computer model microswimmer can adapt its motion to navigate in complex fluid environments without being explicitly programmed to do so.
“Similar to a human learning how to swim, the microswimmer learns how to move its ‘body parts’ — in this case three microparticles and extensible links — to self-propel and turn,” says senior author Alan Tsang, assistant professor of mechanical engineering at the University of Hong Kong. “It does so without relying on human knowledge but only on a machine learning algorithm.”
The ability to switch between gaits is desirable for eventually developing smart artificial micro swimmers that can perform complex biomedical tasks – like targeted drug delivery and microsurgery in people.
Sponge-like electrodes inspired by sugar cubes
Electrodes are often attached to patients’ skin to detect the electrical signals that lie beneath, monitoring things like heart rhythms and muscle function vital to the early diagnosis and treatment of many disorders.
But researchers wanted to make an electrode with more consistent and resilient skin contact than standard electrodes, so they created a low-cost, spongy version made from the template of a sugar cube.
They took commercially available sugar cubes and moulded them into a template that was dipped into liquid polydimethylsiloxane (PDMS) – a silicone polymer – which became solid after being cured. Then, the sugar was dissolved with hot water and the resulting PDMS sponge was coated with a thin film of conductive gel to form the electrode.
The micropores in the spongy electrode allowed it to have increased contact area with the skin, which resulted in strong signal intensity and reduced noise when compared with standard electrodes.