As if ray fish weren’t unusual enough, but it turns out their sperm is also unique in the animal kingdom. Scientists have now created a robot inspired by those sperm, which could one day lead to smaller descendants swimming in the human body.
Most sperm are basically composed of a round tadpole-like head and a floppy tail. That head remains in a fixed direction while the tail either swings back and forth or rotates in a circle relative to it. However, that is not the case with ray sperm.
Due to Dr. Shen Yajing and Shi Jiahai, researchers at City University of Hong Kong recently discovered that those, that Sperm propel themselves by rotating their stiff end along with their soft tails. Furthermore, that tip is long and has a helical (in other words, helical) structure, allowing it to strengthen its way through the fluid medium.
This means that not only can sperm move faster and more efficiently than others, but they can also adapt to moving in liquids of different viscosity by independently adjusting the force. thrust of the head and tail. On analysis, it was determined that the head typically contributes about 31 percent of the total thrust.
As is the case with other sperm, the genetic material transferred to the egg is contained in the head. And the head-to-tail connection is a flexible midsection that powers the rotation. That midsection also allows for enhanced maneuverability, as it allows the sperm to flex like an accordion bus, with both the head and tail rotating to pull it around.
Also, if the sperm encounters an impassable obstacle, it can reverse from it simply by turning its head in the opposite direction. In contrast, the sperm of other animals are incapable of reverse movement.
“Such a non-traditional way of propulsion not only provides the ray spermatozoa with a high degree of adaptability to a variety of viscous media, but also results in superior and efficient motility,” said Dr. “.
The scientists called this motion system a “heterogeneous double helix motor” (HDH) and incorporated it into a ray sperm-inspired robot small enough to fit in the palm of a hand. It consists of a twisted head of hard iron wire, a tail of soft cotton wire and two electric motors in the middle. And for a given power input, it is more adaptive and energy efficient than other swimming robots when moving through different liquids of different viscosity.
It is hoped that one day much smaller versions of the HDH robot could swim through a patient’s body, being able to travel through blood vessels to deliver drugs to specific locations.
The study is described in an article that was recently published in the journal PNAS. You can see the robot in action in the video below.
Robots inspired by swimming biology
Source: City University of Hong Kong