Scientists at Carnegie Mellon built a self-healing skin whose applications could include bio-inspired robots, their colleagues at UCLA found a way to 3D-print muscles and connective tissue, and a team in Norway came up with “evolutionary algorithms” that enabled a robot to teach itself to walk. This week’s science roundup sounds a little like a script for a prequel to a Hollywood blockbuster. Can you name it?
What is it? Researchers at Carnegie Mellon University have developed a “self-healing material that spontaneously repairs itself under extreme mechanical damage.” Carmel Majidi, an associate professor of mechanical engineering at the university, said, “The unprecedented level of functionality of our self-healing material can enable soft-matter electronics and machines to exhibit the extraordinary resilience of soft biological tissue and organisms.”
Why does it matter? The applications could include “bio-inspired robotics, human-machine interaction, and wearable computing,” according to the university. “If we want to build machines that are more compatible with the human body and the natural environment, we have to start with new types of materials,” Majidi said.
How does it work? The researchers made the skin from a composite material of “liquid metal droplets suspended in a soft elastomer,” the university reported. “When damaged, the droplets rupture to form new connections with neighboring droplets and reroute electrical signals without interruption.” Did we just hear you whisper “T-800”?
What is it? Last week we told you about a team at the University of Toronto that developed a handheld device that essentially 3D-prints skin using biomaterials. This week we found out about a research project at the University of California, Los Angeles, using a 3D printer to build complex structures mimicking “parts of muscle tissue and muscle-skeleton connective tissues,” according to the university. When the researchers implanted the structures in cells, their bodies did not reject them. “Tissues are wonderfully complex structures, so to engineer artificial versions of them that function properly, we have to recreate their complexity,” said UCLA engineering professor Ali Khademhosseini, who led the study. “Our new approach offers a way to build complex biocompatible structures made from different materials.”
Why does it matter? The method could be used for tissue engineering and regenerative medicine, the team said in a paper published by the journal Advanced Materials. UCLA said the researchers “also printed shapes mimicking tumors with networks of blood vessels, which could be used as biological models to study cancers.”
How does it work? The team used one of the earliest 3D-printing methods, stereolithography, and customized it to print parts from four different “bio-inks.” The team solidified the hydrogel inks in the right place by sending them through a special microfluidic chip to the build plate. The team then used an array of micromirrors to direct light at the gel, which made it form molecular bonds and become solid.
What is it? Engineers at the University of Oslo in Norway developed a four-legged “mammal-inspired” robot called Dyret that uses evolutionary algorithms to adapt itself to its environment. “For robots to handle the numerous factors that can affect them in the real world, they must adapt to changes and unexpected events,” the team wrote. “Evolutionary robotics tries to solve some of these issues by automatically optimizing a robot for a specific environment.”
Why does it matter? The team said that robots like Dyret “could be ideal for working independently in changing conditions.” They wrote in a paper that “embodied evolution has, however, almost exclusively been applied to the control of a robot,” and that “evolutionary robotics can be used to evolve morphology and adapt a robot’s body to the task it is solving, and the environment where it is doing it.”
How does it work? The robot relies on evolutionary algorithms that initially generate a random gait by varying voltage in the DC motors moving the machine’s reconfigurable legs. Dyret then begins experimenting with a different length and speed of steps and looking for the most optimal approaches.
What is it? Researchers at the KTH Royal Institute of Technology in Stockholm have made the strongest biomaterial known to us — whether natural or synthetic — in their labs. They did it by shaping cellulose nanofibers — the essential building block of trees and plants — in a way “that mimics nature’s ability” to arrange these fibers “into almost perfect macroscale arrangements.”
Why does it matter? The material could find applications in planes, cars, furniture and elsewhere. KTH researcher Daniel Söderberg said the fibers were “8 times stiffer and have strengths higher than natural dragline spider silk fibers, generally considered to be the strongest bio-based material.” Söderberg, who is also the corresponding author of a paper published by ACS Nano, added that the material’s specific strength exceeds “that of metals, alloys, ceramics and E-glass fibers.”
How does it work? The team suspended the nanofibers in deionized and low-pH water in a tiny channel milled in stainless steel. They used the setup to align the nanofibers in the right direction and self-organize “into a well-packed state.” KTH reported that the process “can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibers.”
What is it? Researchers at Purdue University and the Chinese Academy of Sciences have used the gene-editing tool CRISPR/Cas9 to re-engineer “common research rice plants” and make them produce 25 to 31 percent more grain.
Why does it matter? Purdue said it would be “virtually impossible” to achieve the results through traditional breeding methods. “You couldn’t do targeted mutations like that with traditional plant breeding. You’d do random mutations and try to screen out the ones you don’t want,” said Ray Bressan, professor in the department of horticulture and landscape architecture at Purdue. “It would have taken millions of plants. Basically, it’s not feasible.” The team said the next step will be editing the same genes in “elite varieties” of rice. “If this holds true for the varieties that farmers currently use, this big increase in yield would be very important,” said team leader Jian-Kang Zhu of Purdue and also the Shanghai Center for Plant Stress Biology at the Chinese Academy of Sciences. “It would really help produce a lot more grains to feed more people.”
How does it work? The team used CRISPR/Cas9 to edit 13 genes “associated with the phytohormone abscisic acid, known to play roles in plant stress tolerance and suppression of growth,” Purdue said.