Recently, a team at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany, took inspiration from white blood cells to develop a micro-robot that can carry drugs into blood vessels. The robot has a diameter of 3 to 7.8 microns, compared with 8 microns for human red blood cells. While working, the robot enters the blood vessels of cancer patients and moves 600 microns per second in reverse to the flow of blood. Once the cancer cells are found, the robot can release the drug under specific UV stimulation.
The study, published in the robotics journal Science Robotics, is titled “Multifunction Surface Microrollers for targeted cargo transport in blood flow.”
Related links to papers:
First, the robot imitates the white blood cells: move along the walls of blood vessels, identify ingress specific cells
In previous medical practice, micro-robots can only enter organs such as the digestive tract and peritoneal cavity to help generate medical images. It has been envisaged that micro-robots can be put into the human circulation system, so that they can accurately locate the lesions, targeted the drug. But in practice, this idea is difficult to realize because the physical environment in the blood vessels is more complex and is not conducive to the movement of the robot.
Blood flow creates a dense, non-homogeneous fluid environment, while micro-robots that can enter blood vessels are generally less than 10 microns in diameter and have difficulty maintaining propulsion in complex fluid environments.
According to the paper, white blood cells are the only cells that can move along the lining of blood vessels. Researchers at the Max Planck Institute for Intelligent Systems looked closely at how white blood cells move in their blood vessels and found out why they can “reverse the flow” in their blood vessels.
They found that blood flow at the blood stream at the center of the blood vessel slower than at the center of the blood vessel, and that the white blood cells moved along the walls of the blood vessels with less resistance.
Another characteristic of white blood cells is the ability to identify and remove damaged or infected tissue at high temporal and temporal resolutions. This is because there is a “identifying part” in the white blood cells that can identify endothelial cells. When damaged or infected tissue cells are identified, white blood cells bind to them.
The researchers modeled a robot that could move along the cell wall and identify specific cells, following the movement of white blood cells.
Second, spherical robot sriven by magnetic force, 1 second can walk 600 microns
In this study, the researchers designed a spherical miniature robot made of glass particles, ranging in diameter from 3 to 7.8 microns. The robot’s exterior is divided into two and coated with different materials:
Half of the surface of the micro-robot is covered by magnetic nanofilms made of nickel and gold, using magnetic force stoking force, which can move 600 microns per second, equivalent to 76 robot body length! The other half is coated with anti-cancer drugs and molecules that identify cancer cells, which can locate cancer cells and deliver drugs precisely.
The researchers designed ultraviolet light to trigger the robot to release the drug. After irradiating 30s with 365nm of ultraviolet light, the drug is released from the micro-robot.
This study used the breast cancer targeted drug molecule DOX molecule for experiments, in the DOX molecule with fluorescent signals as markers to determine whether the drug was released.
Third, micro-robot scans easily in simulated blood vessels
After designing the robot, the researchers conducted an experiment to test its performance.
First, the researchers used human dermal cell synthesis to simulate blood vessels, in which they injected the whole blood of CD1 in mice. The researchers then put the micro-robot into the blood vessel.
Test results show that when the blood does not flow, the micro-robot in the blood push, navigation is very easy. The researchers further simulated the movement of micro-robots as blood flows. The results showed that both miniature robots were able to move upstream of the blood vessels.
In the case of a blood flow power of 1.2dyn/cm2, the micro-robot with a nickel coating thickness of 480nm moves at a speed of 55.5 to 20.8 m/s, and the robot with a coating thickness of 2 microns moves at a speed of 156.7 to 36.6 m/s.
Conclusion: The next step will be to develop biodegradable robots
The team at the Max Planck Institute for Intelligent Systems took inspiration from white blood cells to develop tiny robots that can carry drugs.
Next, the researchers will continue to work on the technology. According to the paper, the researchers first planned to test the robot in animals. Second, the researchers will try other ways to trigger the drug release process, such as heating or near-infrared light. In addition, researchers will try to make robots from biodegradable materials that can break down in the body in weeks or months.
In the future, micro-robots may be a “magic bullet” for cancer, so let’s see.