Tiny Robots(built to carry drugs) can move against the direction of blood flow and could one day be used to deliver chemotherapy drugs directly to cancer cells.
At the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, Metin Sitti and his colleagues have invented tiny robots called “microrollers” that are capable of carrying cancer drugs and targeting human breast cancer cells.
The design of the robots were inspired by the white blood cells present in the human body, which are able to move along the walls of blood vessels against the direction of blood flow. They are spherical in shape and made with the use of glass microparticles. A part of the robot was coated with a thin magnetic nanofilm made from nickel and gold. While the other part was coated with the cancer drug doxorubicin along with molecules that recognise cancer cells.
Metin Sitti and his colleagues tested the robots in a simulation using mouse blood and synthetic channels lined with human endothelial cells (the ones that line the inner walls of the human blood vessels.) The team exposed the robots to a mixture of healthy and cancerous tissue. The microrollers were able to get selectively attached to the cancer cells and were activated with the use of UV light to release the doxorubicin.
Metin Sitti and his colleagues were able to steer the movement of the microrollers by just applying magnetic fields, both with and against the flow of blood. They say the microrollers can move at a speed of about 600 micrometres per second.
“If you come to a junction in a vascular system where you need to take the right path and if you miss it, then you could go back and go to the right one,” says Setti.
They tested robots that of either 3 and 7.8 micrometres in diameter. Which is small compared to the human red blood cells that are up to 8 micrometres in diameter.
In the coming future, the team plan to use other methods to activate the drug release, like heat or near-infrared light, instead of the UV light they used when testing the robots. They also planning to make microrollers out of biodegradable materials that would break down in the body over a few weeks or months, of course, without causing any harm.
They also have hopes to test the microrollers in animals soon.
“The rollers need to carry enough cancer drugs, which is why we need to have them in large numbers. But since we can locally take them to the right target and deliver it there, we don’t need huge dosages.” says Metin Sitti.