Scientists have developed a microrobot that can deliver medicine exactly where it’s needed using magnets, according to a recent study from ETH Zurich, a Swiss university.
This new technology could enable doctors to dissolve blockages that cause strokes, treat infections with antibiotics, and deliver anti-cancer medication directly to tumours, without side effects elsewhere in the body.
The robot consists of a tiny spherical capsule, made of a dissolvable gel and iron oxide nanoparticles, which are added to make it magnetic. The scientists can track the robot using X-ray tech.
“Because the vessels in the human brain are so small, there is a limit to how big the capsule can be,” said lead author Dr Fabian Landers, a postdoctoral researcher at the Multi-Scale Robotics Lab at ETH Zurich.
“The technical challenge is to ensure that a capsule this small also has sufficient magnetic properties.”
The next challenge was to drive the robot through the maze of blood vessels, navigating twists, junctions and fast-flowing blood.
“It’s remarkable how much blood flows through our vessels and at such high speed,” said Landers. “Our navigation system must be able to withstand all of that.”
So, they developed three ways to drive the microrobot with electromagnets. Depending on the type of magnetic force they used, the scientists were able to roll the robot against the vessel wall or pull it in a certain direction.
With these techniques, the microrobot could travel with or against the current and travel at speeds up to 4mm per second (or one inch every six seconds).
“Magnetic fields and gradients are ideal for minimally invasive procedures because they penetrate deep into the body and – at least at the strengths and frequencies we use – have no detrimental effects on the body,” said last author Prof Bradley Nelson, a microrobot researcher at ETH Zurich.
Once the microrobot reached its target, the scientists could use a high-frequency magnetic field to heat the microrobot, dissolving its shell and releasing the medicine inside.
This invention was tested using silicone models that replicated the blood vessels of humans and animals, as well as in several pigs and the brain of a sheep.
The scientists’ next goal is to begin human clinical trials, so this technology can soon be used in hospital operating theatres.
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