Paramecium and some other bacteria move through the fluid by brushing away hair-like appendages called cilia. Scientists have now developed a type synthetic cilia, which could be used in microrobots and beyond.
Cilia protrudes from the microorganism’s body, propelling it through the liquid medium by repeatedly reaching forward and then sweeping back. They do not do so in unison but instead begin to move individually, in turn, creating waves that travel the length of the bacteria.
Researchers have have produced larger-scale artificial cilia before, but these systems tend to be quite mechanically complex and too large to incorporate into small devices. However, a team from the Netherlands’ Eindhoven University of Technology recently created a tiny mollusk robot that uses a much simpler, smaller form of cilia.
To do so, the scientists combined a liquid polymer with carbonyl iron powder particles, then poured the mixture into an array of 50-micrometer-wide cylindrical pores that served as templates for the cilia. As the polymer cures to a rubbery consistency, magnets placed underneath the mold cause the iron particles to arrange themselves differently in the adjacent cilia – this gives each cilium a different magnetic quality. .
The finished 4 mm long robot consists of a solid polymer base, with cilia protruding from one side. When it was placed with the cilia facing up – in a water/glycol solution – the application of a rotating magnetic field caused the cilia to move back and forth in waves. This allows the device to act like a pump, as the moving appendages cause liquid to rapidly flow through it.
When the robot is flipped, the cilia are on the bottom, their movement allows the device to move on a flat surface. It can even crawl up 45-degree slopes and carry a load 10 times its own weight. And when the direction of the rotating magnetic field is reversed, the robot also reverses the direction in which it is moving.
It is now hoped that, once further developed, the technology could be used in applications such as pumps in microfluidic systems or microrobots used to deliver drugs or food. perform other functions inside the patient’s body.
The study is described in a paper that was recently published in the journal Materials & Application Interface ACS. You can see the robot in action via the link below.
Source: American Chemical Society