TechTheDay

Even with Moore’s Law coming to an end, miniaturization in technology is expected to continue. The shrunk down bezels in smartphones and tablets, batteries that are able to store more power in a smaller body, cameras going mirrorless and adopting curved sensors to become more compact, and various other efforts in coming up with devices in smaller sizes are expected to continue in many ways. Recently,  scientists have come up with super tiny propellers, as reported in a paper published in the June 2014 issue of ACS Nano, that are expected to become useful in undertaking health-related procedures that require immense precision.

The World’s Smallest Propeller

The word “propeller” typically brings to mind something large and highly capable of  propulsion. It has to be something big enough to generate the force necessary to move an object. That’s why if you’re looking for the world’s smallest ever propeller, you’d probably be surprised to learn that it’s actually as small as small can get. This propeller is so small that it belongs to the realm of nanotechnology. It can be used within the human body.

The world’s smallest propeller is the result of the R&D work of Technion and German researchers. Technion is the Israel Institute of Technology, Israel’s oldest university with notable development and innovative strengths in science, technology, and engineering. The German researchers are from the Max Planck Institute for Intelligent Systems and the University of Stuttgart’s Institute for Physical Chemistry.

This uber-tiny propeller is run by an external rotating magnetic field. It is extremely small, around 70 nanometers in diameter and 400 meters in length, that it can be used to propel a nanorobot inside the human body and even within living cells. It is screw-shaped, a design which allows it to easily move in gel-like fluids. To put things in perspective, this minute propeller is considerably smaller than the body’s cells. According to Peer Fischer, one of the members of the research team, the propeller is around 100 times smaller than the human blood cell. Fischer adds that the propeller is so small that even the Brownian motion of living cells affects its movement.

Testing the Propeller’s Usability

That the propeller can enable motion in liquids is already a given for the scientists involved in the project. Hence the goal was quickly shifted to enabling movement and motion control within the human body. To test whether it can be used inside an organism’s body, the team used hyaluronan, an anionic nonsulfated glycosaminoglycan present in the human body, found in connective, epithelial, and neural tissues. Hyaluronan has properties that prove challenging for the mobility of nanometer-sized materials. The researchers successfully maneouvered the propellers by employing a relatively weak rotating magnetic field.

The team was surprised with what they achieved. Given the size of the nano-propellers, natural movements induced by diffusion were expected to make it very difficult to control the propellers. However, because the propellers’ size was comparable to the size of the mesh in the hyaluronan, the propellers moved with relative ease. According to Associate Professor Leshanksy of the Technion Faculty of Chemical Engineering, the propellers “actually display significantly enhanced propulsion velocities, exceeding the highest speeds measured in glycerin as compared with micro-propellers, which show very low or negligible propulsion.”

Applications

So far, there have been no demonstrations of the actual applications or uses of the nano-propeller technology. However, it is expected to become highly useful in the field of medicine, particularly in drug delivery. The nano-propellers have been shown to be capable of penetrating the cell with the aid of a relatively low magnetic field. Fischer opines: “one can now think about targeted applications, for instance in the eye where they may be moved to a precise location at the retina.” He adds that this new technology could also be coupled with “active molecules” at the tips to facilitate targeted radiation treatments.

Hopefully, great things not just in the field of medicine will come out of this nano-propeller development. It can be an option for the precise targeting of cancer cells. The potential applications of this nanotechnology appear to be very wide and exciting.