Researchers have created a robotic mimic of a stingray that’s powered and guided by light-sensitive rat heart cells.
The work exhibits a new method for building bio-inspired robots by means of tissue engineering. Batoid fish, which include stingrays, are distinguished by their flat bodies and long, wing-like fins that extend from their heads. These fins move in energy-efficient waves that emulate from the front of the fin to the back, allowing batoids to glide gracefully through water. Inspired by this design, Sung-Jin Park et al. endeavored to build a miniature, soft tissue robot with similar qualities and efficiency. They created neutrally charged gold skeletons that mimic the stingray’s shape, which were overlaid with a thin layer of stretchy polymer.
The sea urchin’s intricate mouth and teeth are the model for a claw-like device developed by a team of engineers and marine biologists at the University of California, San Diego to sample sediments on other planets, such as Mars. The researchers detail their work in a recent issue of the Journal of Visualized Experiments.
The urchin’s mouthpiece was first described in detail by the Greek philosopher Aristotle, earning it the nickname “Aristotle’s lantern.” It is comprised of an intricate framework of muscles and five curved teeth with triangle-shaped tips that can scrape, cut, chew and bore holes into the toughest rocks—a colony of sea urchins can destroy an entire kelp forest by churning through rock and uprooting seaweed. The teeth are arranged in a dome-like formation that opens outwards and closes inwards in a smooth motion, similar to a claw in an arcade prize-grabbing machine.
The urchin’s extraordinary ability to rip through rock could translate to a good sediment sampler for space vehicles like the Mars rovers, which currently use shovels to collect ground samples, said Michael Frank, a Ph.D. candidate at the Jacobs School of Engineering at UC San Diego and the paper’s first author. “Our goal was a bioinspired device that’s more precise and efficient at grabbing ground samples from different areas, and won’t disturb the surrounding area like a shovel would,” he said.
Frank is part of a research group that uses engineering to explain biological structures and then designs bio-inspired devices based on what they find. Led by mechanical engineering professor Joanna McKittrick, the group has applied this approach to exploring natural structures in seahorses, boxfish, porcupines, woodpeckers, porcupine fish and many other animals.
Researchers look to bones and shells as blueprints for stronger, more durable concrete.
Researchers at MIT are seeking to redesign concrete — the most widely used human-made material in the world — by following nature’s blueprints.
In a paper published online in the journal Construction and Building Materials, the team contrasts cement paste — concrete’s binding ingredient — with the structure and properties of natural materials such as bones, shells, and deep-sea sponges. As the researchers observed, these biological materials are exceptionally strong and durable, thanks in part to their precise assembly of structures at multiple length scales, from the molecular to the macro, or visible, level.
From their observations, the team, led by Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering (CEE), proposed a new bioinspired, “bottom-up” approach for designing cement paste.
“These materials are assembled in a fascinating fashion, with simple constituents arranging in complex geometric configurations that are beautiful to observe,” Buyukozturk says. “We want to see what kinds of micromechanisms exist within them that provide such superior properties, and how we can adopt a similar building-block-based approach for concrete.”
Inspired by the humble cactus, a new type of membrane has the potential to significantly boost the performance of fuel cells and transform the electric vehicle industry.
The membrane, developed by scientists from CSIRO and Hanyang University in Korea, was described today in the journal Nature . The paper shows that in hot conditions the membrane, which features a water repellent skin, can improve the efficiency of fuel cells by a factor of four.
According to CSIRO researcher and co-author Dr Aaron Thornton, the skin works in a similar way to a cactus plant, which thrives by retaining water in harsh and arid environments.
“Fuel cells, like the ones used in electric vehicles, generate energy by mixing together simple gases, like hydrogen and oxygen. However, in order to maintain performance, proton exchange membrane fuel cells – or PEMFCs – need to stay constantly hydrated,” Dr Thornton said.
“At the moment this is achieved by placing the cells alongside a radiator, water reservoir and a humidifier. The downside is that when used in a vehicle, these occupy a large amount of space and consume significant power,” he said.
According to CSIRO researcher and co-author Dr Cara Doherty, the team’s new cactus-inspired solution offers an alternative
INSPIRED BY A DESERT BEETLE, CACTUS AND PITCHER PLANT, RESEARCHERS DESIGN A NEW MATERIAL TO COLLECT WATER DROPLETS
Organisms such as cacti and desert beetles can survive in arid environments because they’ve evolved mechanisms to collect water from thin air. The Namib desert beetle, for example, collects water droplets on the bumps of its shell while V-shaped cactus spines guide droplets to the plant’s body.
As the planet grows drier, researchers are looking to nature for more effective ways to pull water from air. Now, a team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University have drawn inspiration from these organisms to develop a better way to promote and transport condensed water droplets.
“Everybody is excited about bioinspired materials research,” said Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science at SEAS and core faculty member of the Wyss Institute. “However, so far, we tend to mimic one inspirational natural system at a time. Our research shows that a complex bio-inspired approach, in which we marry multiple biological species to come up with non-trivial designs for highly efficient materials with unprecedented properties, is a new, promising direction in biomimetics.”
The new system, described in Nature, is inspired by the bumpy shell of desert beetles, the asymmetric structure of cactus spines and slippery surfaces of pitcher plants. The material harnesses the power of these natural systems, plus Slippery Liquid-Infused Porous Surfaces technology (SLIPS) developed in Aizenberg’s lab, to collect and direct the flow of condensed water droplets.
This approach is promising not only for harvesting water but also for industrial heat exchangers.
“Thermal power plants, for example, rely on condensers to quickly convert steam to liquid water,” said Philseok Kim, co-author of the paper and co-founder and vice president of technology at SEAS spin-off SLIPS Technologies, Inc. “This design could help speed up that process and even allow for operation at a higher temperature, significantly improving the overall energy efficiency.”
The major challenges in harvesting atmospheric water are controlling the size of the droplets, speed in which they form and the direction in which they flow.
For years, researchers focused on the hybrid chemistry of the beetle’s bumps — a hydrophilic top with hydrophobic surroundings — to explain how the beetle attracted water. However, Aizenberg and her team took inspiration from a different possibility – that convex bumps themselves also might be able to harvest water.
“We experimentally found that the geometry of bumps alone could facilitate condensation,” said Kyoo-Chul Park, a postdoctoral researcher and the first author of the paper. “By optimizing that bump shape through detailed theoretical modeling and combining it with the asymmetry of cactus spines and the nearly friction-free coatings of pitcher plants, we were able to design a material that can collect and transport a greater volume of water in a short time compared to other surfaces.”
“Without one of those parameters, the whole system would not work synergistically to promote both the growth and accelerated directional transport of even small, fast condensing droplets,” said Park.
“This research is an exciting first step towards developing a passive system that can efficiently collect water and guide it to a reservoir,” said Kim.
Learn more: Pulling water from thin air
Stem cells hold great potential for addressing a variety of conditions from spinal cord injuries to cancer, but they can be difficult to control.
Scientists are now reporting in the journal ACS Nano a new way to mimic the body’s natural approach to programming these cells. Using this method, they successfully directed adult stem cells to turn specifically into muscle, which could potentially help treat patients with muscular dystrophy.