In a world’s first, a team at the City University of Hong Kong has developed a magnetic 3D-printed microscopic robot that can carry cells to precise locations in human bodies in vivo.

The size of the new microbot is less than 100 micrometers in diameter, similar to that of a single strand of human hair.

Using computer simulations, researchers assessed the efficiency of different robot designs and found that a porous burr-shaped structure could be optimal for carrying cell loads and moving through bloodstreams and body fluid.

The microbots can be used to carry stem cells to repair damaged tissues or treat tumors, providing an alternative to invasive surgery, as well as a solution for the side effects caused by drugs and drug resistance, said team leader Professor Sun Dong, head of the university’s Department of Biomedical Engineering.

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The porous burr-shaped structure of the minuscule microbot is optimal for carrying cell loads through blood vessels and even capillaries. Photo: Handout

The invention has the potential to revolutionize cell-based therapy and regenerative medicine for more precise treatment of diseases such as cancer.

The microbots are manufactured using 3D laser lithography, coated with nickel for magnetism and titanium for biocompatibility.

An external electromagnetic coil actuation system, also developed by CityU, is used to guide the magnetic microbots through blood vessels to reach a desired location after injection.

Subsequent tests were carried out on two types of animals. The researchers loaded the microbots with connective tissue cells and stem cells, injected them into transparent zebrafish embryos, and used a magnet to guide them to the desired location.

In addition, microbots carrying fluorescent cancer cells were injected into lab rats. These cells were successfully transported to the targeted locations. Cancer cells were used in the experiment because they could be easily detected after forming a tumor.

The team is also conducting a pre-clinical study on delivering stem cells into animals for the precise treatment of liver cancers. Clinical studies on humans are expected to take place in two to three years.

It took the team 10 years to overcome the challenges in different disciplines such as biomedical sciences, nanotechnology and robotics.