The idea of micrometer-scaled instruments and robots has been in minds of scientists for a long time. As the nanotechnology field emerged in 1980s, they grew more serious about it. The final breakthrough recently came when an engineer at the Drexel University discovered a new technique for fabrication of very minute sized swimmers with least geometric requirements in a liquid. The new microrobots move in the liquid like a bacterial flagella with the help of two conjoined microparticles that are coated with magnetic iron oxide debris. These particles exhibit a behaviour like that when these are exposed to an outer magnetic field.
Figure 1: Minimalist Micrometer Robots Movement
These particle-inspired robots are made with chemical conjugation along with magnetic self-assembly. The new method of fabrication was preferred over the regular methods as specialized chemistry and lithography techniques have better scope. Min Jun im, the professor of mechanics and mechanical engineering at the Drexel University, further adds, "Such simple microswimmers circumvent the technical limitations of fabrication technologies, which effectively allow for a focus on the functionalization of microswimmers. Furthermore, the use of particles to create these microswimmers will synergize well with other micro- and nanoparticle–based technologies such as nanoparticle drug delivery systems."
The new method of locomotion used by these particles takes advantage of negligible inertial forces that are found at a very low positioned Reynolds number in fluids and liquids. Gradually, as the viscous forces get more dominant, the robots begin to depend over nonreciprocal motion created through their rotation. Kim points out that since the strong electromagnetic systems fixed wth the microscopic particles present around microrobot’ chamber, these particles were able to exert good amount of force on the swimmers. He also adds "Our results demonstrated successful control over the microswimmers' swimming speed and direction. The significance of the results is the demonstration that such extremely simple microswimmers can be fully controllable at low Reynolds number." He hopes to expand the research in coming time in a systematic manner. The best application of this technology will be used in the nanotechnology field particles like these will mainly assist in surgical methods or delivering special dosages of drugs inside human body.