Nano-sized fish that are remotely controlled and able to swim in liquids when a magnetic field is applied have been developed by a combined team of researchers from the University of California in the USA and the Harbin Institute of Technology in China.
Previous attempts to build minute bio-transport mechanisms have usually been based on the corkscrew tailed model of bacteria. The researchers in this study however, thought a better approach would be to imitate the way fish swim. To achieve this, they connected nickel and gold segments with silver hinges. The inner segments serve as the fish body and the outer segments made of gold serve as the tail and the head. The complete fish is a hundred times smaller than a grain of salt, with each segment measuring a mere 800 nanometers in length.
An oscillating magnetic field is applied to force the tail and head to swing, causing the fish to swim and propelling it forward. The speed at which the fish moves and the direction it takes is controlled by varying the position and speed of the oscillating magnet.
The team’s purpose in developing these nanoswimmers is to use them to carry medicine to a specific part of the body. This would reduce the need for surgery or unnecessary use of drugs and eliminate negative side effects in other parts of the body.
In a video released by the team, they show not only the speed at which the fish can travel, but also demonstrate the ease with which they can be controlled. This new version is obviously an improvement over other nano delivery systems.
The team admits that there are still some issues that need to be addressed before the tiny fish really become viable for production. One of the challenges is how to rid the body of the swimmers after they have delivered their package. One possible solution would be to use biodegradable material in the construction. Although the amount of precious metals used to create a single fish is small, this could quickly add up and become prohibitive if hundreds of the fish were used to deliver medicine doses. Micro steering would also have to be built into the fish’s system by developing a means for tracking the fish.
The research team has published their research in the journal Nano Small Micro.