Metals, Stents, and Nanobots
Atherosclerosis – caused by the deposition of fat, cholesterol, calcium and other substances on the inner walls of the arteries – is the process by which blood vessels harden and narrow. It is a major medical issue that limits the ability of oxygen-rich blood to reach vital organs, thereby increasing an individual’s risk of heart attack or stroke.
In the past, physicians have used angioplasty or bypass surgery to either break up or circumvent the occluding plaque, but these methods have not always effective and are far from ideal. Currently, drug-eluting stents, self-expanding stents, and stents of various novel components (like magnesium for example) represent the cutting edge in atherosclerosis treatment (and as such are being heavily researched by scientists hoping to make a leap forward in the treatment of this disease).
Interestingly, “nanobots” have also been deployed to deal with serious medical threat. In 2015, a research team based in Drexel University demonstrated that they had created a micro-robotic technology capable of drilling through plaque buildup in clogged arteries. The micro-robots they discuss take the form of small microbeads with the ability to join together and form a corkscrew-like structure. These robots are made up of tiny iron oxide beads, with an average diameter of 400 nanometers, joined together in a long chain. Importantly, the Drexel researchers have reported that these beads are “composed of inorganic, biocompatible materials that will not trigger an immunological response.”
The exciting capability of these micro-robots is revealed when the beads are exposed to a magnetic field. When a bead chain is exposed to a finely tuned external magnetic field, they can be induced to move through the bloodstream. The rotation of a finely tuned magnetic field causes the bead chain to form a spinning helical structure that propels itself through the bloodstream. The properties of the aforementioned magnetic field control the speed, direction, and size of the chain, thus affecting the force with which it moves. After being injected into the body via catheter and manipulated by the magnetic field, these drill-like micro-robots can be directed to the site of an arterial occlusion. Upon deployment, the bead chains will drill into plaque buildups, loosening them. The plaques can then be finished off by a small surgical drill delivered via catheter to the site of the occlusion. After the surgery, the biodegradable beads release anticoagulant drugs into the bloodstream to help prevent future plaque buildup at the site.
The use of magnetic fields to transform metal micro-bead chains into small spinning drills is an incredibly novel idea. It represents the creativity necessary to develop nano- and micro-robots into effective therapeutic tools capable of making a difference in patient’s lives.
References
https://www.smithsonianmag.com/innovation/tiny-robots-can-clear-clogged-arteries-180955774/
https://www.sciencealert.com/graphene-based-nanobots-could-clean-up-the-metal-from-our-oceans