Researchers from Polytechnique Montréal, Université de Montréal and McGill University have developed nanorobots capable of navigating through the bloodstream to administer a drug that specifically targets the active cancerous cells of tumors.

This way of administering medication ensures the optimal targeting of a tumor and avoids jeopardizing the integrity of organs and surrounding healthy tissues. As a result, drug dosages that are highly toxic for the human organism can be significantly reduced.

“These legions of nanorobotic agents were actually composed of more than 100 million flagellated bacteria—and therefore self-propelled—and loaded with drugs that moved by taking the most direct path between the drug’s injection point and the area of the body to cure,” says Professor Sylvain Martel, director of the Polytechnique Montréal Nanorobotics Laboratory, who heads the research team’s work.

The nanorobots are composed of more than 100 million flagellated bacteria. Image credit: Polytechnique Montréal Nanorobotics Laboratory. When they enter a tumor, the nanorobotic agents can detect in a wholly autonomous fashion the oxygen-depleted tumor areas, known as hypoxic zones, and deliver the drug to them. This hypoxic zone is created by the substantial consumption of oxygen by rapidly proliferative tumor cells. Hypoxic zones are known to be resistant to most therapies, including radiotherapy.

To move around, the bacteria used by Professor Martel’s team rely on two natural systems. A kind of compass created by the synthesis of a chain of magnetic nanoparticles allows them to move in the direction of a magnetic field, while a sensor measuring oxygen concentration enables them to reach and remain in the tumor’s active regions. By harnessing these two transportation systems and exposing the bacteria to a computer-controlled magnetic field, researchers showed that these bacteria could act as artificial nanorobots.

“This innovative use of nanotransporters will have an impact not only on creating more advanced engineering concepts and original intervention methods, but it also throws the door wide open to the synthesis of new vehicles for therapeutic, imaging and diagnostic agents,” Martel says. “Chemotherapy, which is so toxic for the entire human body, could make use of these natural nanorobots to move drugs directly to the targeted area, eliminating the harmful side effects while also boosting its therapeutic effectiveness.”