Redefining how anti-cancer drugs are administered


Refining our attack on cancer cells

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It's being touted as a spectacular breakthrough in cancer research. Researchers from Polytechnique Montréal, Université de Montréal and McGill University have developed new nanorobotic agents capable of navigating through the bloodstream and administering drugs that can then precisely target a tumor's active cancerous cells.

This way of injecting medication avoids jeopardizing the integrity of organs and healthy tissues near the site of the tumor. As a result, a drug dosage that is highly toxic for the human organism can be significantly reduced.

The researchers successfully administered nanorobotic agents into the colorectal tumors of mice.

"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," explains Professor Sylvain Martel, holder of the Canada Research Chair in Medical Nanorobotics and director of the Polytechnique Montréal Nanorobotics Laboratory, who heads the research team's work. "The drug's propelling force was enough to travel efficiently and enter deep inside the tumors."

When they enter a tumor, 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.

But gaining access to tumors by taking paths as minute as a red blood cell and crossing complex physiological micro-environments does not come without challenges. So Professor Martel and his team used nanotechnology to do it.


Bacteria with compass

To move around, 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 by exposing the bacteria to a computer-controlled magnetic field, researchers showed that these bacteria could perfectly replicate artificial nanorobots of the future designed for this kind of task.

Using nanotransporters can certainly lead to more advanced engineering concepts and original intervention methods in the fight against cancer, but it also means that chemotherapy, which is so toxic for the entire human body, can finally step into the 21st century. These natural nanorobots can move drugs directly to targeted areas, eliminating harmful side effects while also boosting therapeutic effectiveness. It can mean the actual improvement of patient outcomes and signify a much more tangible form of hope. 

The team's findings were published this week in the journal Nature Nanotechnology in an article titled "Magneto-aerotactic bacteria deliver drug-containing nanoliposomes to tumor hypoxic regions."