Artificial bacteria flagella that act as surgical micro robots

Commentary on:
Medical Micro-Robots Made As Small As Bacteria
in ScienceDaily (Apr. 19, 2009)
http://www.sciencedaily.com/releases/2009/04/090418085333.htm

Medical 'microbot' to swim human arteries
in Cosmos Magazine. By Agence France-Presse (Jan. 21, 2009)
http://www.cosmosmagazine.com/news/2484/medical-microbot-swim-human-arteries?page=0%2C0


This new biomimetic technology seems like something out of the Magic School Bus kids' book series. Imagine tiny self-propelling microbots that can enter the bloodstream and deliver drugs, remove plaque from clots, do micro-scale surgeries, etc. all under the control of a physician. This science-fiction-esque future of medicine is becoming increasingly feasible with the recent invention of the “Artificial Bacterial Flagella” (ABFs). They were invented, manufactured and enabled to swim in a controllable way by researchers in the group led by Bradley Nelson, Professor at the Institute of Robotics and Intelligent Systems at ETH Zurich. There are many other pioneers working in this field of medical microbots, as well.

What is unique about these microscopic microbots is how remarkably they resemble flagella bacteria. They range in size from 25-65 micrometers in length while bacteria are only slightly smaller at 5-25 micrometers and they move just as bacteria do--via propulsion from the spiral whip-like tail based precisely on that of the bacteria. These artificial bacteria are made of ultra-thin layers of the elements indium, gallium, arsenic and chromium vapor-deposited onto a substrate in a particular sequence which forms super-thin, very long narrow ribbons that curl themselves into a spiral shape as soon as they are detached from the substrate. There is also a tiny "head" attached to one end made out of chromium-nickel-gold tri-layer film which is slightly-magnetic. This magnetism is what allows the bacteria to propel itself and be controlled by scientists without using any energy or moving parts. "The ABF can be steered to a specific target by tuning the strength and direction of the rotating magnetic field which is generated by several coils. The ABFs can move forwards and backwards, upwards and downwards, and can also rotate in all directions." As of now these ABFs can swim at about the same speed as bacteria but scientists predict that they will be able to create ABFs that can swim at least 3 times as fast.

ABFs are still undergoing basic research and its healthcare applications are far in the future, however, with the invention of these ABFs the use of microbots in medicine is becoming increasingly feasible. One of the earliest applications of this technology will probably be for observation such as through transmitting images. Nelson believes that ABFs could eventually be used on the cellular level to repair cell damage, remove plaque, among other surgical applications, which will greatly expand the ability of today's healthcare to treat a wide variety of diseases and disorders. In theory, the ABFs could be injected into the bloodstream and then controlled via an external remote control and then once done traveling where needed and performing the necessary tasks, they would be removed via syringe at the point of entry.

With further development the technology will likely become much more accurate than physician surgery and will go far beyond what any physician today can do. This may revolutionize surgery, however, it has potential applications beyond surgery including drug-delivery. If ABFs can carry medicines to the exact target cells and areas that need them, the side effects that develop from today's systemic drugs will be a thing of the past. The impact of this technology on the cost of healthcare will depend on the application. Drug-delivery will be more expensive if ABFs are used than the standard pill-form, however some surgeries may be less expensive with the use of microbots. Many diseases like atherosclerosis that are very common in the U.S. are prime candidates for this technology and because of this, microbots have the potential to have a tremendous impact on the healthcare industry in the future.

The ability of Nelson's team to create an artificial bacteria that so accurately resembles the structure and function of a flagella bacteria opens up endless possibilities for biomedical applications and proves that the use of microbots in medicine may not be too far off in the future.