Arterial traffic: microbots can deliver cargo in live animals

A new type of microscopic robot may help revolutionise the way we treat damaged tissues, according to research from the City University of Hong Kong. 

The burr-shaped, 3D-printed microrobot can be injected into the bloodstream and then guided to a specific area of the body using an external magnetic field.  

The robot’s unique structure allows it to transport and release a load of cells at the desired location — including stems cells, which aid in tissue regeneration and restoration.

This is the first known instance of a microrobot being able to carry and deliver cells in a live body, writes lead researcher Junyang Li and colleagues in a study published in Science Robotics. 

Magnetic devices have been used before to manipulate individual cells, with designs ranging from U-shaped robots to minuscule syringes. While these tools have been limited to in vitro trials, the new burr structure produced by Li and colleagues opens the door to use microrobots to treat a range of medical conditions in living people. 

Potential clinical applications of this non-invasive technology include targeted drug delivery, regenerative medicine and other cell-based therapies. {%recommended 6470%}

To design a robot capable of navigating such a complex system, researchers initially used computer simulations to assess how well different shapes moved through arteries and veins. Porous, burr-shaped microrobots outperformed their cubical counterparts, showing a greater ability to carry cell loads and move through viscous blood. 

Once 3D-printed, the microrobots were coated in nickel, for magnetism, and titanium, for biocompatibility. Subsequent tests with zebrafish embryos and mice showed that the mini-machines were successful at delivering their cargo to targeted areas. 

Scientists were able to track the robots’ progress through the test animals in two ways: visually, in the transparent zebrafish embryos; and by using fluorescence microscopes to locate robot-delivered cell loads in the mice. 

However, Li and colleagues note that advances in materials science and real-time imaging need to occur in lockstep with microrobot design before the technology can be widely adopted.