In their early stages of formation, starfish embryos are like tiny glass balls that float in the water.

A recent study published in the journal Nature on July 13, conducted by scientists from the Massachusetts Institute of Technology in the United States, indicated that these embryos rotate in a spinning motion and are attracted to each other and spontaneously assemble into a structure Regular crystals.

strange behavior

Even more surprising is the ability of these "living crystals" to behave with unusual flexibility.

As the spinning of each individual unit of these embryos leads to ripples in the collective structure of these crystals.

The researchers found that this undulating crystal formation can persist for relatively long periods before dissipating as the embryos mature.

"It is absolutely wonderful to see these glass globe embryos floating on the surface in a formation with a perfect crystalline structure," says Nikta Fakhry, assistant professor of physics at the institute and lead of the study.

"Perhaps this crystal structure offers some advantages that we don't know yet, as flocks of birds do to avoid predators or to fly more smoothly," Fakhry adds.

In addition, we can simulate this undulating, self-assembled crystal shape to design robots that move and work collectively.

"The interactions between starfish embryos open new doors to explore their physical properties. This may enable us to design flexible robots that can rotate and interact with each other similarly as these embryos do," Fakhri notes.

A chance discovery

It is worth noting that the starfish is an ideal model that scientists use in studying the stages of growth and development of embryos.

That's because it contains relatively large cells and is optically transparent.

Fakhri recalled that this discovery was "purely coincidental".

Her research group has been studying how starfish embryos develop, and specifically how embryonic cells divide in their early stages.

The wavy crystal formation of embryos can persist for long periods before dissipating (social networking sites)

The researchers were watching how the fetuses swim as they matured.

Once fertilized, these embryos grow and divide, forming a shell from which small hairs or cilia grow, pushing the embryo through the water.

At a certain moment, these cilia combine to push the embryo to rotate in a specific direction (spiral deflection).

The team noticed that when the embryos swim to the surface, they continued to spiral toward each other.

hexagonal crystals

"Small groups of these embryos gather and dance from time to time. There are other marine creatures that do the same thing, such as some algae," Fakhri said.

"This was intriguing and made us wonder what would happen if there were so many of these groups," she says.

So the team fertilized thousands of starfish embryos, and then watched their behavior on the surface of lab dishes.

She says that "when there were thousands of these embryos in the same dish, I started to form this crystal structure that grew in size very large. We described them as crystals, because each embryo was surrounded by 6 embryos in a hexagonal shape that repeated throughout the entire structure and resembled the crystal structure. for graphene.

Each embryo was surrounded by 6 embryos in a hexagonal shape that repeated across the entire structure (social networking sites)

To find out the reasons why embryos gather in this hexagonal shape, the team studied how the water current flows around a single embryo.

They put a single starfish embryo in water, then added much smaller pellets, and took pictures of the pellets as they flowed around the embryo on the surface of the water.

vibrating crystals

The team found that the cilia on the surface of the embryo hit the water in a way that causes the embryo to rotate in a certain direction creating vortices on the sides, which in turn pull the tiny globules into it.

The results of the simulation conducted by the team confirmed the occurrence of the same behavior that the team observed in practical experiments.

Which confirms that it is a behavior resulting from the physical interactions of the pellets with each other.

The team also noted that once this crystal structure forms, it lasts for several days.

During this period, spontaneous ripples begin to spread across the entire structure.

Fakhri notes that the research team was able to "see these crystals spin and vibrate for a very long time. This was not expected, as we initially thought that these ripples would disappear quickly due to the viscosity of the water, which will dampen these oscillations. However, this system showed that it has Strange behavior.

Individual cycles of fetuses can create greater mass movement across the entire structure (social networking sites)

Long-lasting spontaneous ripples may be the result of interactions between individual embryos, which rotate opposite each other like interlocking gears.

With thousands of these gears spinning in a crystal formation, many individual rotations of the embryos can create greater mass movement through the entire structure.

The researchers are now studying the presence of this phenomenon in other organisms, such as sea urchins, which exhibit similar crystallographic behavior.

They are also studying how to simulate this self-assembled structure in robotic systems.