An international team of scientists has taken its inspiration from fish in designing nanorobotic technology. The group’s tiny swimming robots, which are controlled by external magnetic fields, could be used in medical applications, such as minimally invasive surgery, drug delivery, or single-cell manipulation.
The nanoswimmers are a collaborative project developed at the University of California, San Diego (UCSD) and the Harpin Institute of Technology in China by teams led by Joseph Wang and Longqiu Li. The research builds on a previous study published by the UCSD team in 2011; the technology’s newest iteration is smaller and easier to control.
Each “fish” is approximately 800 nanometers long and is composed of a gold head and tail fin, nickel body, and silver hinges, as reported by New Scientist. When an oscillating magnetic field is applied, the nickel components sway from side to side in a motion that moves the head and fins, causing the nanorobot to “swim” through liquid. By changing the magnetic field, researchers can control both direction and speed.
“The swimming locomotion of fish involves complex interplay between a deformable body and induced flow in the surrounding liquid,” wrote the study authors in a paper published by Small. While underwater robotics inspired by fish have been developed in the past, the research team claims its nanofishes are the smallest ever designed, exhibit “high swimming efficiency,” and can serve as “promising biomimetic nanorobotics devices.”
“A lot of work on drug delivery vehicles relies on the body’s transport systems to move the particles to the site of the pathology,” nanotechnology expert Justin Gooding of the University of New South Wales, Australia (who was not part of the study), told New Scientist. “However, active transport has recently begun to be explored, and this work shows that active transport particles can be made smaller and faster.”
Recent microrobotic technology developed at the Ecole Polytechnique Federale de Lausanne and nanorobots introduced by Canadian scientists — both directed by external magnets — were designed to move like bacteria. Pharmaceutical giant Pfizer recently partnered with the Bar Ilan University Research and Development Company (BIRAD) to evaluate drug-delivery capabilities of nanorobotics crafted with strands of DNA.
Li told New Scientist that his team’s nanofish were “more efficient” than the corkscrew design of bacteria-inspired nanoswimmers, though he acknowledged that his system had some considerable limitations. At this time, the researchers are working to develop a system for either removing the nanofish from the body or using biodegradable materials in their design. When the system’s biocompatibility is improved, Li commented that the fish could provide an efficient method of drug delivery, noninvasive surgery, or cell manipulation.
“Humanity has not succeeded yet in developing a machine that can communicate directly with biologic structures, processes and affect it by doing so,” said Ido Bachelet, director of the bio-design lab at BIRAD. “However, the development of such machines may have dramatic consequences on our lives and may enable us to help manage and control processes in our body just as they are forming.”