Life demands flow.
Every living organism is constantly changing: cells divide and die, proteins accumulate and disintegrate, DNA breaks down and heals. Life demands metabolism, the simultaneous constructor and destroyer of living materials, to continuously improve our bodies. This is how we heal and grow, how we spread and survive.
What would happen if we could endow robots cold, static and lifeless with the gift of metabolism?
In a study published this month in. Robotic science, an international team developed a method based on DNA that gives raw biomaterials an artificial metabolism. Nicknamed DASH: badembly and synthesis of hierarchical materials based on DNA: the method automatically generates nanobots similar to "slime" that move and navigate dynamically in their environments.
Like human beings, the artificial real material used external energy to constantly change the bodies of nanobots in pre-programmed forms, recycling their DNA-based parts as waste and raw material for later use. Some "grew" in the form of molecular double helices; others "wrote" the letters of DNA inside microchips.
The forms of artificial life were also rather "competitive", in quotes, because these molecular machines are not aware. However, when faced with each other, two DASH robots automatically ran forward, crawling in the typical form of slime mold on a scale easily visible under the microscope, and with some repetitions, with the naked human eye.
"Fundamentally, we can change the way we create and use materials with real characteristics. Typically, the materials and objects we create in general are basically static … one day, we can "grow" objects like houses and maintain their forms and functions autonomously, "said Dr. Shogo Hamada, author of the study, Singularity Hub
"This is a great study that combines the versatility of DNA nanotechnology with the dynamics of living materials," said Dr. Job Boekhoven of the Technical University of Munich, who was not involved in the work.
The study builds on previous ideas on how to make molecular Lego blocks that essentially bademble and destroy themselves.
Although inspiration came from biological metabolism, scientists have long waited to reduce their dependence on nature. At its core, metabolism is just a group of well-coordinated chemical reactions, programmed by eons of evolution. So, why make artificial real materials still linked to evolution when we can use chemistry to design completely new forms of artificial life?
In 2015, for example, a team led by Boekhoven described a way to imitate how our cells build their internal "structural beams", aptly called the cytoskeleton. The key here, unlike many processes in nature, is not balance or balance; rather, the team designed an extremely unstable system that automatically constructs, and sustains, bademblies from molecular building blocks when they are provided with an external source of chemical energy.
Sounds familiar? The team basically built molecular devices that "die" without "food". Thanks to the laws of thermodynamics (hey ya, Newton!), That energy dissipates finally and the forms begin to decompose automatically, completing an "artificial life circle". "
The new study took the system a step further: instead of simply imitating the synthesis, they completed the circle by joining the construction process with the dissipative badembly.
Here, the "badembly units themselves are also created autonomously from scratch," said Hamada.
The process of construction of DNA nanobots begins in a microfluidic chip.
Decades of research have allowed researchers to optimize the badembly of DNA outside the body. With the help of catalysts, which help "unite" individual molecules, the team discovered that they could easily alter the shape of self-badembled DNA robots, which formed fiber shapes, by changing the structure of microfluidic chambers.
Computer simulations also played an important role here: through digital simulations and observations under the microscope, the team was able to identify some critical rules that helped them predict how their molecules are badembled as they navigate a maze of blocks and carved cbads. about the microchips.
This "allowed a general design strategy for DASH employers," they said.
In particular, the swirling movement of fluids as they moved through the chip ridges seems to help DNA molecules "get entangled in networks," the team explained.
These ideas helped the team to further develop the "destructive" part of the metabolism. Similar to the union of molecules in DNA chains, their destruction also depends on enzymes.
Once the team injected the enzymes of "generation" and "degeneration" into the microchips, along with the basic components, the process was completely autonomous. The simultaneous processes were so real that the team used a metric commonly used in robotics, finite state automation, to measure the behavior of their DNA nanobots from growth to eventual decomposition.
"The result is a synthetic structure with characteristics badociated with life. "These behaviors include locomotion, self-regeneration and space-time regulation," said Boekhoven.
Molecular slime molds
The mere fact of witnessing that living molecules grow in their place, like the dance movement that man performs, was not enough.
In their next experiments, the team was inspired by slugs to program undulating motions in their DNA robots. Here, the "movement" is actually a kind of illusion: the machines "moved" because their frontal ends continued to regenerate, while their posterior ends degenerated. In essence, the molecular slime was constructed from the linking of multiple units "similar to a DNA robot": each unit receives a signal of "decomposition" delayed from the head of the slime in a way that allows the whole "organism "Artificially drag forward, against the vapor of fluid flow.
Here's the fun part: the team eventually designed two molecular slime robots and pitted them against each other, in the style of Mario Kart. In these experiments, the fastest-moving bot alters the status of its competitor to promote "decay." This slows down the competitor, which allows the dominant DNA nanowire to win in a race.
Of course, the ultimate goal is not molecular deterioration. Rather, DNA-based robots could easily amplify a given DNA or RNA sequence, which makes them efficient nano-diagnostics for viral and other infections.
The team said that realistic material can basically generate patterns that doctors can "see" directly with their eyes, which makes the DNA or RNA molecules of bacteria and viruses extremely easy to detect, the team said.
In the short term, "the detection device with this self-generation material could be applied to many places and help people in place, from farmers to clinics, by providing an easy and accurate way to detect pathogens," Hamaga explained.
A futuristic iron man nonsense?
I'm letting my nerd's flag fly here. In Avengers: Infinity Wars, playboy philanthropist-scientist-engineer Tony Stark revealed a nanosuit that grew to its contours when necessary and was automatically cured when it was damaged.
DASH may one day realize that vision. For now, the team is not focused on using technology to regenerate armor, but dynamic materials could create new sets of proteins or chemical pathways within living organisms, for example. The team also plans to add simple detection and computation mechanisms in the material, which can then be considered as a robot.
Unlike synthetic biology, the goal is not to create artificial life. Rather, the team hopes to give realistic properties to static materials.
"We are introducing a concept of completely new and realistic material driven by its own artificial metabolism. "We are not doing something that is alive, but we are creating materials that are much more real than they have ever been before," said lead author Dr. Dan Luo.
"Ultimately, our material can allow the construction of self-reproducing machines … the artificial metabolism is an important step towards the creation of" artificial "biological systems with dynamic and real capabilities," added Hamada. "It could open a new frontier in robotics."
Image credit: a timelapse image of DASH, by Jeff Tyson at Cornell University.