Swarms of magnetic bacteria have been used to deliver chemotherapy drugs to tumors without exposing healthy tissue to their toxic effects in a groundbreaking study published in the journal Nature Nanotechnology.
Researchers, funded by the National Institute of Biomedical Imaging and
Bioengineering (NIBIB), were able to show how bacteria could be used to efficiently deposit tumor-fighting drugs right to the low-oxygen centre of cancerous tumors.
Nanocarriers do already exist that are able to deliver drugs to the cancerous cells, but only in very low quantities and never to the low-oxygen regions at the centre of tumors.
“Only a very small proportion of drugs reach the hypoxic zones, which are believed to be the source of metastasis. Therefore, targeting the low-oxygen regions will most likely decrease the rate of metastasis while maximizing the effect of a therapy,” said Lead researcher and Director of the Polytechnique Montréal NanoRobotics Laboratory Dr Slyvain Martel.
The scientists used Magnetococcus marinus, a species of bacteria that thrives in low-oxygen, deep water. To migrate whilst remaining in these regions, the bacteria rely on a two-part system. First, tiny magnetic crystals line up inside their cells like a compass needle pointing them North and second, sensors that detect oxygen levels allow them to stay within low oxygen areas.
Dr Martel and his team directed the bacteria loaded with chemotherapy drugs by creating a magnetic field around the tumors. They then switched off the magnetic field and allowed the bacteria to use their low oxygen sensors to direct themselves to the centre of the tumors where the drugs were delivered, attacking the tumors from the centre and protecting the healthy cells from the effects of the drugs.
“These bacteria are really the perfect machine. They replicate, they’re cheap, and we can inject hundreds of millions or more at a time,” said Dr Martel.