Millirobots speed medicine to the heart

Wireless magnetic millirobots the size of a pencil tip could one day replace open-heart surgery and ineffective drug therapy.
Engineers at Johns Hopkins University have created pencil-tip-sized robots designed to travel through the body and deliver medicine to infections within a beating heart.
The bots, designed to replace open-heart surgery and ineffective IV drug therapy for life-threatening heart infections, could also treat other hard-to-reach diseases, including cancer, less invasively and more precisely.
Senior author Axel Krieger, a medical roboticist, said: ‘With just a little pinprick, you insert a micro robot and do a procedure without infection or blood loss. And you don’t need to have a surgeon operating it to get the drugs robustly, safely and efficiently to the right place. There are a lot of areas beyond heart infections where this kind of targeted drug therapy and these kinds of steerable robots could play a major role. It’s really the frontier of surgical robotics.’
The work is newly published in Advanced Material Technologies.
The typical treatment for endocarditis – a weeks-long course of intravenous antibiotics –often fails because the drugs are too diluted by the time they reach the heart.
This leaves physicians with two choices: prescribing more and higher doses of antibiotics, which can be toxic, or open-heart surgery.
To deliver drugs directly to infected heart tissue, the team developed magnetically powered millirobots that work in pairs.
The needle module gently latches onto heart tissue at the infected site. There, it serves as a docking station, waiting right on the beating heart for the drug module. The drug module carries medicine to the docking station where it magnetically docks and slowly releases the antibiotics right where they’re most needed.
Both robots are guided wirelessly by an external electromagnetic coil system that works like an MRI machine.
Using two tiny robots instead of one larger one lets the device reach tight spots in the body. The needle can remain docked while the drug module is replaced, allowing repeat doses of medicine if needed.
In addition to eliminating the need for open-heart surgery, drug treatment with the robots could take hours instead of weeks.
The researchers next plan to test the robots in more realistic phantom hearts that mimic muscle contraction and the beating motion of a real heart.